Showing 1–13 of 13 results for author: Raj, R

Thermal Degradation Mechanisms and Stability Enhancement Strategies in Perovskite Solar Cells: A Review

Authors: Arghya Paul, Kanak Raj, Prince Raj Lawrence Raj, Pratim Kumar

Abstract: Perovskite Solar Cells (PSCs) have garnered global research interest owing to their superior photovoltaic (PV) performance. The future of photovoltaic technology lies in PSCs since they can produce power with performance on par with the best silicon solar cells while being less expensive. PSCs have enormous potential; in just ten years, their efficiency increased from 3.8% to 25.2%, and research i… ▽ More Perovskite Solar Cells (PSCs) have garnered global research interest owing to their superior photovoltaic (PV) performance. The future of photovoltaic technology lies in PSCs since they can produce power with performance on par with the best silicon solar cells while being less expensive. PSCs have enormous potential; in just ten years, their efficiency increased from 3.8% to 25.2%, and research into new developments is still ongoing. Thermal instability is PSCs' main disadvantage, despite their high efficiency, flexibility, and lightweight nature. This paper looks at how temperature affects the ways that hole transport layers (HTLs) like spiro-OMeTAD and perovskite layers, especially MAPbI3, degrade. Elevated temperatures cause MAPbI3 to degrade into PbI2, CH3I, and NH3, with decomposition rates affected by moisture, oxygen, and environmental factors. Mixed cation compositions, such as Cs-MA-FA, have higher thermal stability, whereas MA+ cations break-down faster under heat stress. HTLs deteriorate due to morphological changes and the hydrophilicity of dopant additions like Li-TFSI and t-BP. Alternative dopant-free HTMs, such as P3HT and inorganic materials including CuSCN, NiOx, and Cu2O, have shown improved thermal stability and efficiency. Hybrid HTLs, dopant-free designs, and interface tweaks are all viable solutions for increasing the stability of PSC. Addressing thermal stability issues remains crucial for the development of more reliable and efficient PSC technology. △ Less

Submitted 17 September, 2025; originally announced September 2025.

Identifying nonequilibrium degrees of freedom in high-dimensional stochastic systems

Authors: Catherine Ji, Ravin Raj, Benjamin Eysenbach, Gautam Reddy

Abstract: Any coarse-grained description of a nonequilibrium system should faithfully represent its latent irreversible degrees of freedom. However, standard dimensionality reduction methods typically prioritize accurate reconstruction over physical relevance. Here, we introduce a model-free approach to identify irreversible degrees of freedom in stochastic systems that are in a nonequilibrium steady state.… ▽ More Any coarse-grained description of a nonequilibrium system should faithfully represent its latent irreversible degrees of freedom. However, standard dimensionality reduction methods typically prioritize accurate reconstruction over physical relevance. Here, we introduce a model-free approach to identify irreversible degrees of freedom in stochastic systems that are in a nonequilibrium steady state. Our method leverages the insight that a black-box classifier, trained to differentiate between forward and time-reversed trajectories, implicitly estimates the local entropy production rate. By parameterizing this classifier as a quadratic form of learned state representations, we obtain nonlinear embeddings of high-dimensional state-space dynamics, which we term Latent Embeddings of Nonequilibrium Systems (LENS). LENS effectively identifies low-dimensional irreversible flows and provides a scalable, learning-based strategy for estimating entropy production rates directly from high-dimensional time series data. △ Less

Submitted 14 August, 2025; v1 submitted 11 August, 2025; originally announced August 2025.

High-Performance Ultra-Wide-Bandgap CaSnO3 Metal-Oxide-Semiconductor Field-Effect Transistors

Authors: Weideng Sun, Junghyun Koo, Donghwan Kim, Hongseung Lee, Rishi Raj, Chengyu Zhu, Kiyoung Lee, Andre Mkhoyan, Hagyoul Bae, Bharat Jalan, Gang Qiu

Abstract: The increasing demand for high-voltage and high-power electronic applications has intensified the search for novel ultrawide bandgap (UWB) semiconductors. Alkaline earth stannates possess wide band gaps and exhibit the highest room-temperature electron mobilities among all perovskite oxides. Among this family, Calcium stannate (CaSnO3) has the largest band gap of ~4.7 eV, holding great promise for… ▽ More The increasing demand for high-voltage and high-power electronic applications has intensified the search for novel ultrawide bandgap (UWB) semiconductors. Alkaline earth stannates possess wide band gaps and exhibit the highest room-temperature electron mobilities among all perovskite oxides. Among this family, Calcium stannate (CaSnO3) has the largest band gap of ~4.7 eV, holding great promise for high-power applications. However, the demonstration of CaSnO3 power electronic devices is so far limited. In this work, high-performance metal-oxide-semiconductor field-effect transistor (MOSFET) devices based on La-doped CaSnO3 are demonstrated for the first time. The MOSFETs exhibit an on/off ratio exceeding 10^8, along with field-effect mobility of 8.4 cm2 V-1 s-1 and on-state current of 30 mA mm-1. The high performance of the CaSnO3 MOSFET devices can be ascribed to the excellent metal-to-semiconductor contact resistance of 0.73 kΩμm. The devices also show great potential for harsh environment operations, as high-temperature operations up to 400 K have been demonstrated. An off-state breakdown voltage of 1660 V is achieved, with a breakdown field of ~8.3 MV cm-1 among the highest reported for all UWB semiconductors. This work represents significant progress toward realizing the practical application of CaSnO3 in future high-voltage power electronic technologies. △ Less

Submitted 30 June, 2025; originally announced June 2025.

Scalable Etch-Free Transfer of Low-Dimensional Materials from Metal Films to Diverse Substrates

Authors: Kentaro Yumigeta, Muhammed Yusufoglu, Mamun Sarker, Rishi Raj, Franco Daluisio, Richard Holloway, Howard Yawit, Thomas Sweepe, Julian Battaglia, Shelby Janssen, Alex C. Welch, Paul DiPasquale, K. Andre Mkhoyan, Alexander Sinitskii, Zafer Mutlu

Abstract: Low-dimensional materials hold great promises for exploring emergent physical phenomena, nanoelectronics, and quantum technologies. Their synthesis often depends on catalytic metal films, from which the synthesized materials must be transferred to insulating substrates to enable device functionality and minimize interfacial interactions during quantum investigations. Conventional transfer methods,… ▽ More Low-dimensional materials hold great promises for exploring emergent physical phenomena, nanoelectronics, and quantum technologies. Their synthesis often depends on catalytic metal films, from which the synthesized materials must be transferred to insulating substrates to enable device functionality and minimize interfacial interactions during quantum investigations. Conventional transfer methods, such as chemical etching or electrochemical delamination, degrade material quality, limit scalability, or prove incompatible with complex device architectures. Here, a scalable, etch-free transfer technique is presented, employing Field's metal (51% In, 32.5% Bi, and 16.5% Sn by weight) as a low-melting-point mechanical support to gently delaminate low-dimensional materials from metal films without causing damage. Anchoring the metal film during separation prevents tearing and preserves material integrity. As a proof of concept, atomically precise graphene nanoribbons (GNRs) are transferred from Au(111)/mica to dielectric substrates, including silicon dioxide (SiO_2) and single-crystalline lanthanum oxychloride (LaOCl). Comprehensive characterization confirms the preservation of structural and chemical integrity throughout the transfer process. Wafer-scale compatibility and device integration are demonstrated by fabricating GNR-based field-effect transistors (GNRFETs) that exhibit room-temperature switching with on/off current ratios exceeding 10^3. This method provides a scalable and versatile platform for integrating low-dimensional materials into advanced low-dimensional materials-based technologies. △ Less

Submitted 27 June, 2025; originally announced June 2025.

Studying the Seebeck coefficient and exploring the possibility of enhancing ZT upto 1.8 for NaCo$_2$O$_4$ in high temperature region

Authors: Rahul Raj, Sudhir K. Pandey

Abstract: Here, we have studied the temperature dependent Seebeck coefficient (S) of the NaCo$_2$O$_4$ (NCO) by using experimental and computational methods. The range of experimentally obtained S is $\sim$55 to 103 $μ$V/K in the temperature range of 300-600 K, which confirms the p-type behaviour of NCO. The electronic structure of this compound is obtained via DFT+U formalism. The band dispersion and parti… ▽ More Here, we have studied the temperature dependent Seebeck coefficient (S) of the NaCo$_2$O$_4$ (NCO) by using experimental and computational methods. The range of experimentally obtained S is $\sim$55 to 103 $μ$V/K in the temperature range of 300-600 K, which confirms the p-type behaviour of NCO. The electronic structure of this compound is obtained via DFT+U formalism. The band dispersion and partial density of states confirms the magnetic and half metallic nature. Furthermore, in the transport properties, the obtained S using a U = 4 eV gives the best match with experimental data. The temperature and chemical potential dependent S$^{2}$$σ$$/$$τ$ is calculated using the obtained electronic transport properties, in which the maximum value obtained for p(n)-type doping is $\sim$22(61)$\times$10$^1$$^4$ $μ$WK$^{-2}$cm$^{-1}$s$^{-1}$. The possibility of enhancing the ZT is identified, and it is calculated in temperature range 300-1200 K. The maximum calculated value of ZT is 0.64 for p-type and 1.8 for n-type doping at 1200 K. The calculated carrier concentration obtained for p(n) type doping at 1200 K is $\sim$1.17 (1.6)$\times$10$^2$$^2$ cm$^-$$^3$. This study suggests that the careful doping of p and n type can enhance the applicability of this compound in thermoelectric for high temperature application. △ Less

Submitted 5 May, 2025; originally announced May 2025.

Growth-Induced Unconventional Magnetic Anisotropy in Co/Fullerene (C60) Bilayer Systems; Insights from a Two-Grain Stoner-Wohlfarth Model

Authors: Sonia Kaushik, Rakhul Raj, Pooja Gupta, R Venkatesh, Andrei Chumakov, Matthias Schwartzkopf, V Raghavendra Reddy, Dileep Kumar

Abstract: Organic spintronics has drawn the interest of the science community due to various applications in spin-valve devices. However, an efficient room-temperature Organic Spin Valve device has not been experimentally realized due to the complicated spin transport at the metal-organic interfaces. The present study focuses on a comprehensive understanding of the interfacial properties essential for advan… ▽ More Organic spintronics has drawn the interest of the science community due to various applications in spin-valve devices. However, an efficient room-temperature Organic Spin Valve device has not been experimentally realized due to the complicated spin transport at the metal-organic interfaces. The present study focuses on a comprehensive understanding of the interfacial properties essential for advancing device performance and functionality. The structural and magnetic properties of the ultra-thin Cobalt (Co) films deposited on the fullerene (C60) layer are studied to investigate the origin of magnetic anisotropy in the metal-organic bilayer structures. Due to the mechanical softness of C60, penetration of ferromagnetic Co atoms inside the C60 film is confirmed by the X-ray reflectivity and Secondary Ion Mass Spectroscopy measurements. Grazing incidence small-angle X-ray scattering and atomic force microscopy provided information regarding the structural and morphological properties of the Co/C60 bilayers, angular dependent Magneto-optic Kerr effect measurements with varying Co layer thickness provided information about the growth-induced uniaxial magnetic anisotropy. In contrast to the inorganic silicon substrates, magnetic anisotropy in Co film tends to develop at 25 Å thickness on the C60 layer, which further increases with the thickness of Cobalt. The anomalous behavior in coercivity and remanence variation along the nominal hard axis is explained by a two-grain Stoner-Wohlfarth model with intergranular exchange coupling. It is further confirmed by a non-uniform spatial distribution of magnetic domains investigated through Kerr microscopy. These anomalies could be attributed to the distribution of magneto-crystalline anisotropy and inhomogeneous strain caused by the formation of a diffused layer at the Co/C60 interface. △ Less

Submitted 14 September, 2024; originally announced September 2024.

Comments: 18 pages, 13 Figures

Structural and electronic transformations in TiO2 induced by electric current

Authors: Tyler C. Sterling, Feng Ye, Seohyeon Jo, Anish Parulekar, Yu Zhang, Gang Cao, Rishi Raj, Dmitry Reznik

Abstract: In-situ diffuse neutron scattering experiments revealed that when electric current is passed through single crystals of rutile TiO2 under conditions conducive to flash sintering, it induces the formation of parallel planes of oxygen vacancies. Specifically, a current perpendicular to the c-axis generates planes normal to the (132) reciprocal lattice vector, whereas currents aligned with the c-axis… ▽ More In-situ diffuse neutron scattering experiments revealed that when electric current is passed through single crystals of rutile TiO2 under conditions conducive to flash sintering, it induces the formation of parallel planes of oxygen vacancies. Specifically, a current perpendicular to the c-axis generates planes normal to the (132) reciprocal lattice vector, whereas currents aligned with the c-axis form planes normal to the (132) and to the (225) vector. The concentration of defects increases with incresing current. The structural modifications are linked to the appearance of signatures of interacting Ti3+ moments in magnetic susceptibility, signifying a structural collapse around the vacancy planes. Electrical conductivity measurements of the modified material reveal several electronic transitions between semiconducting states (via a metal-like intermediate state) with the smallest gap being 27 meV. Pristine TiO2 can be restored by heating followed by slow cooling in air. Our work suggests a novel paradigm for achieving switching of electrical conductivity related to the flash phenomenon △ Less

Submitted 21 October, 2024; v1 submitted 12 September, 2024; originally announced September 2024.

Skyrmion-mediated Nonvolatile Ternary Memory

Authors: Md Mahadi Rajib, Namita Bindal, Ravish Kumar Raj, Brajesh Kumar Kaushik, Jayasimha Atulasimha

Abstract: Multistate memory systems have the ability to store and process more data in the same physical space as binary memory systems, making them a potential alternative to existing binary memory systems. In the past, it has been demonstrated that voltage-controlled magnetic anisotropy (VCMA) based writing is highly energy-efficient compared to other writing methods used in non-volatile nano-magnetic bin… ▽ More Multistate memory systems have the ability to store and process more data in the same physical space as binary memory systems, making them a potential alternative to existing binary memory systems. In the past, it has been demonstrated that voltage-controlled magnetic anisotropy (VCMA) based writing is highly energy-efficient compared to other writing methods used in non-volatile nano-magnetic binary memory systems. In this study, we introduce a new, VCMA-based and skyrmion-mediated non-volatile ternary memory system using a perpendicular magnetic tunnel junction (p-MTJ) in the presence of room temperature thermal perturbation. We have also shown that ternary states {-1, 0, +1} can be implemented with three magnetoresistance values obtained from a p-MTJ corresponding to ferromagnetic up, down, and skyrmion state, with 99% switching probability in the presence of room temperature thermal noise in an energy-efficient way, requiring ~3 fJ energy on an average for each switching operation. Additionally, we show that our proposed ternary memory demonstrates an improvement in area and energy by at least 2X and ~60X respectively, compared to state-of-the-art spin-transfer torque (STT)-based non-volatile magnetic multistate memories. Furthermore, these three states can be potentially utilized for energy-efficient, high-density in-memory quantized deep neural network implementation. △ Less

Submitted 17 May, 2023; originally announced May 2023.

Structural changes induced by electric currents in a single crystal of Pr$_2$CuO$_4$

Authors: Susmita Roy, Feng Ye, Zachary Morgan, Syed I. A. Jalali, Yu Zhang, Gang Cao, Nobu-Hisa Kaneko, Martin Greven, Rishi Raj, Dmitry Reznik

Abstract: We demonstrate a novel approach to the structural and electronic property modification of perovskites, focusing on Pr$_2$CuO$_4$, an undoped parent compound of a class of electron-doped copper-oxide superconductors. Currents were passed parallel or perpendicular to the copper-oxygen layers with the voltage ramped up until a rapid drop in the resistivity was achieved, a process referred to as "flas… ▽ More We demonstrate a novel approach to the structural and electronic property modification of perovskites, focusing on Pr$_2$CuO$_4$, an undoped parent compound of a class of electron-doped copper-oxide superconductors. Currents were passed parallel or perpendicular to the copper-oxygen layers with the voltage ramped up until a rapid drop in the resistivity was achieved, a process referred to as "flash". The current was then further increased tenfold in current-control mode. This state was quenched by immersion into liquid nitrogen. Flash can drive many compounds into different atomic structures with new properties, whereas the quench freezes them into a long-lived state. Single-crystal neutron diffraction of as-grown and modified Pr$_2$CuO$_4$ revealed a $\sqrt{10}$x$\sqrt{10}$ superlattice due to oxygen-vacancy order. The diffraction peak intensities of the superlattice of the modified sample were significantly enhanced relative to the pristine sample. Raman-active phonons in the modified sample were considerably sharper. Measurements of electrical resistivity, magnetization and two-magnon Raman scattering indicate that the modification affected only the Pr-O layers, but not the Cu-O planes. These results point to enhanced oxygen-vacancy order in the modified samples well beyond what can be achieved without passing electrical current. Our work opens a new avenue toward electric field/quench control of structure and properties of layered perovskite oxides. △ Less

Submitted 7 September, 2023; v1 submitted 8 February, 2023; originally announced February 2023.

Journal ref: Phys. Rev. Materials 7, 083803 (2023)

Two-dimensional diffusiophoretic colloidal banding: Optimizing the spatial and temporal design of solute sinks and sources

Authors: Ritu R. Raj, C. Wyatt Shields IV, Ankur Gupta

Abstract: In this work, we numerically investigate the impact of two-dimensional solute gradients on the distribution of colloidal particles, i.e., colloidal banding, induced via diffusiophoresis. The solute gradients are generated by spatially arranged sources and sinks that emit/absorb a time-dependent solute flux. First we study a dipole system, i.e., one source and one sink, and discover that interdipol… ▽ More In this work, we numerically investigate the impact of two-dimensional solute gradients on the distribution of colloidal particles, i.e., colloidal banding, induced via diffusiophoresis. The solute gradients are generated by spatially arranged sources and sinks that emit/absorb a time-dependent solute flux. First we study a dipole system, i.e., one source and one sink, and discover that interdipole diffusion and flux decay timescales dictate colloidal banding. At timescales shorter than the interdipole diffusion timescale, we observe a rapid enhancement in particle enrichment around the source due to repulsion from the sink. However, at timescales longer than the interdipole diffusion timescale, the source and sink screen each other, leading to a slower enhancement. If the solute flux decays at the timescale of interdipole diffusion, an optimal separation distance is obtained such that particle enrichment is maximized. We find that the partition coefficient between solute inside the source and the bulk strongly impacts the optimal separation distance. Surprisingly, the diffusivity ratio between solute in the source and bulk has a much weaker impact on the optimal dipole separation distance. We also examine an octupole configuration, i.e., four sinks and four sources, arranged in a circle, and demonstrate that the geometric arrangement that maximizes enrichment depends on the radius of the circle. If the radius of the circle is small, it is preferred to have sources and sinks arranged in an alternating fashion. However, if the radius of the circle is large, a consecutive arrangement of sources and sinks is optimal. Our numerical framework introduces a novel method for spatially and temporally designing the banded structure of colloidal particles in two dimensions using diffusiophoresis and opens up new avenues in a field that has primarily focused on one-dimensional solute gradients. △ Less

Submitted 9 January, 2023; v1 submitted 24 November, 2022; originally announced November 2022.

Probing site-resolved correlations in a spin system of ultracold molecules

Authors: Lysander Christakis, Jason S. Rosenberg, Ravin Raj, Sungjae Chi, Alan Morningstar, David A. Huse, Zoe Z. Yan, Waseem S. Bakr

Abstract: Synthetic quantum systems with interacting constituents play an important role in quantum information processing and in elucidating fundamental phenomena in many-body physics. Following impressive advances in cooling and trapping techniques, ensembles of ultracold polar molecules have emerged as a promising synthetic system that combines several advantageous properties. These include a large set o… ▽ More Synthetic quantum systems with interacting constituents play an important role in quantum information processing and in elucidating fundamental phenomena in many-body physics. Following impressive advances in cooling and trapping techniques, ensembles of ultracold polar molecules have emerged as a promising synthetic system that combines several advantageous properties. These include a large set of internal states for encoding quantum information, long nuclear and rotational coherence times and long-range, anisotropic interactions. The latter are expected to allow the exploration of intriguing phases of correlated quantum matter, such as topological superfluids, quantum spin liquids, fractional Chern insulators and quantum magnets. Probing correlations in these phases is crucial to understand their microscopic properties, necessitating the development of new experimental techniques. Here we use quantum gas microscopy to measure the site-resolved dynamics of quantum correlations in a gas of polar molecules in a two-dimensional optical lattice. Using two rotational states of the molecules, we realize a spin-1/2 system where the particles are coupled via dipolar interactions, producing a quantum spin-exchange model. Starting with the synthetic spin system prepared far from equilibrium, we study the evolution of correlations during the thermalization process for both spatially isotropic and anisotropic interactions. Furthermore, we study the correlation dynamics in a spin-anisotropic Heisenberg model engineered from the native spin-exchange model using Floquet techniques. These experiments push the frontier of probing and controlling interacting systems of ultracold molecules, with prospects for exploring new regimes of quantum matter and characterizing entangled states useful for quantum computation and metrology. △ Less

Submitted 19 July, 2022; originally announced July 2022.

Journal ref: Nature 614, 64 (2023)

Light-induced giant and persistent changes in the converse magnetoelastic effects in Ni/BaTiO3 multiferroic heterostructure

Authors: Anita Bagri, Anupam Jana, Gyanendra Panchal, Rakhul Raj, Mukul Gupta, V. R. Reddy, Deodatta Moreshwar Phase, Ram Janay Choudhary

Abstract: Magnetoelastic and magnetoelectric coupling in the artificial multiferroic heterostructures facilitate valuable features for device applications such as magnetic field sensors and electric write magnetic-read memory devices. In a ferromagnetic/ferroelectric heterostructures, the strain mediated coupling exploits piezoelectricity/electrostriction in ferroelectric phase and magnetostriction/piezomag… ▽ More Magnetoelastic and magnetoelectric coupling in the artificial multiferroic heterostructures facilitate valuable features for device applications such as magnetic field sensors and electric write magnetic-read memory devices. In a ferromagnetic/ferroelectric heterostructures, the strain mediated coupling exploits piezoelectricity/electrostriction in ferroelectric phase and magnetostriction/piezomagnetism in ferromagnetic phase. Such verity of these combined effect can be manipulated by an external perturbation, such as electric field, temperature or magnetic field. Here, we demonstrate the remote-controlled tunability of these effects under the visible, coherent and polarized light. The combined surface and bulk magnetic study of domain-correlated Ni/BaTiO3 heterostructure reveals that the system is strong sensitive about the light illumination via the combined effect of converse piezoelectric, magnetoelastic coupling and converse magnetostriction. Well-defined ferroelastic domain structure is fully transferred from a tetragonal ferroelectric to magnetostrictive layer via interface strain transfer during the film growth. The visible light illumination is used to manipulate the original ferromagnetic microstructure by the light-induced domain wall motion in ferroelectric, consequently the domain wall motion in the ferromagnetic layer. Our findings mimic the attractive remote-controlled ferroelectric random-access memory write and magnetic random-access memory read application scenarios, hence, can be proven as a novel perspective for room temperature device applications. △ Less

Submitted 8 July, 2022; v1 submitted 1 July, 2022; originally announced July 2022.

Comments: 35 pages, 7 figures

Low temperature synthesis, magnetic and magnetotransport properties of (La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12) system

Authors: D. Das, M. R. Raj, D. Bahadur, C. M. Srivastava, A. K. Nigam, S. K. Malik

Abstract: We have been able to synthesize Lu+3 substituted La0.67Ca0.33MnO3 (LCMO) by an auto-combustion method. Synthesis of this compound is not successful by conventional ceramic or other chemical methods. Magnetic and electrical transport properties of the Lu substituted LCMO [(La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12)] system have been investigated and compared with those of the Y+3, Pr+3, Dy+3 and Tb+3… ▽ More We have been able to synthesize Lu+3 substituted La0.67Ca0.33MnO3 (LCMO) by an auto-combustion method. Synthesis of this compound is not successful by conventional ceramic or other chemical methods. Magnetic and electrical transport properties of the Lu substituted LCMO [(La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12)] system have been investigated and compared with those of the Y+3, Pr+3, Dy+3 and Tb+3 substituted LCMO systems. All the compounds show a ferromagnetic metal to paramagnetic insulator transition at TC. The tolerance factor reduces from 0.917 for x = 0 to 0.909 for x = 0.12 and for this range all are ferromagnetic metals indicating the dominance of the coupling between spins due to double exchange over the antiferromagnetic superexchange interaction. The transition temperatures and magnetization decrease as the Lu concentration increases. This is satisfactorily accounted for on the basis of transition from ferromagnetic at x = 0 to canted spin order for x > 0. All the samples show higher magnitude of MR compared to that in pure LCMO at 80 kOe field in the temperature range of 5 to 320K. A fairly high value of low field magnetoresistance (LFMR) of about 30% is obtained in all the samples at a field less than 5 kOe. △ Less

Submitted 6 August, 2004; originally announced August 2004.

Comments: Total 35 pages of text and figures