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Transmission of low energy electrons through a polyethylene terephthalate 800-nm diameter nanocapillary
Authors:
Li Pengfei,
Liu Wanqi,
Ha Shuai,
Pan Yuzhou,
Fan Xuhong,
Du Zhanhui,
Wan Chengliang,
Cui Ying,
Yao Ke,
Ma Yue,
Yang Zhihu,
Shao Caojie,
Reinhold Schuch,
Lu Di,
Song Yushou,
Zhang Hongqiang,
Chen Ximeng
Abstract:
The transmission of 2-keV electrons through a polyethylene terephthalate (PET) nanocapillary with a diameter of 800 nm and a length of 10 μm is studied. The transmitted electrons are detected using a microchannel plate (MCP) with a phosphor screen. It is found that the transmission rate for the transmitted electrons at the incident energy can reach up to 10% for an aligned capillary in the beam di…
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The transmission of 2-keV electrons through a polyethylene terephthalate (PET) nanocapillary with a diameter of 800 nm and a length of 10 μm is studied. The transmitted electrons are detected using a microchannel plate (MCP) with a phosphor screen. It is found that the transmission rate for the transmitted electrons at the incident energy can reach up to 10% for an aligned capillary in the beam direction, but drops to less than 1% when the tilt angle exceeds the geometrically allowable angle. The transmitted electrons with the incident energy do not move with changes in the tilt angle, so the incident electrons are not guided in the insulating capillary, which is different from the behavior of positive ions. In the final stage of transmission, the angular distribution of the transmitted electrons within the geometrically allowable angle splits into two peaks along the observation angle perpendicular to the tilt angle. The time evolution of the transmitted complete angular distribution shows that when the beam is turned on, the transmission profile forms a single peak. As the incident charge and time accumulate, the transmission profile begins to stretch in the plane perpendicular to the tilt angle and gradually splits into two peaks. When the tilt angle of the nanocapillary exceeds the geometrically allowable angle, this splitting tends to disappear. Simulation of charge deposition in the capillary directly exposed to the beam indicates the formation of positive charge patches, which are not conducive to guiding, unlike positive ions. Based on the simulation results, we can explain our data and discuss the possible reasons for the splitting of the transmission angular profiles.
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Submitted 13 April, 2025;
originally announced April 2025.
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Field-free superconducting diode effect and magnetochiral anisotropy in FeTe0.7Se0.3 junctions with the inherent asymmetric barrier
Authors:
Shengyao Li,
Ya Deng,
Dianyi Hu,
Chao Zhu,
Zherui Yang,
Wanghao Tian,
Xueyan Wang,
Ming Yue,
Qiong Wu,
Zheng Liu,
Xiao Renshaw Wang
Abstract:
Nonreciprocal electrical transport, characterized by an asymmetric relationship between current and voltage, plays a crucial role in modern electronic industries. Recent studies have extended this phenomenon to superconductors, introducing the concept of the superconducting diode effect (SDE). The SDE is characterized by unequal critical supercurrents along opposite directions. Due to the requirem…
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Nonreciprocal electrical transport, characterized by an asymmetric relationship between current and voltage, plays a crucial role in modern electronic industries. Recent studies have extended this phenomenon to superconductors, introducing the concept of the superconducting diode effect (SDE). The SDE is characterized by unequal critical supercurrents along opposite directions. Due to the requirement on broken inversion symmetry, the SDE is commonly accompanied by electrical magnetochiral anisotropy (eMCA) in the resistive state. Achieving a magnetic field-free SDE with field tunability is pivotal for advancements in superconductor devices. Conventionally, the field-free SDE has been achieved in Josephson junctions by intentionally intercalating an asymmetric barrier layer. Alternatively, internal magnetism was employed. Both approaches pose challenges in the selection of superconductors and fabrication processes, thereby impeding the development of SDE. Here, we present a field-free SDE in FeTe0.7Se0.3 (FTS) junction with eMCA, a phenomenon absent in FTS single nanosheets. The field-free property is associated with the presence of a gradient oxide layer on the upper surface of each FTS nanosheet, while the eMCA is linked to spin-splitting arising from the absence of inversion symmetry. Both the SDE and eMCA respond to magnetic fields with distinct temperature dependencies. This work presents a versatile and straightforward strategy for advancing superconducting electronics.
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Submitted 16 October, 2024;
originally announced October 2024.
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Prethermal time-crystalline spin ice and monopole confinement in a driven magnet
Authors:
Mingxi Yue,
Zi Cai
Abstract:
Studies on systems far from equilibrium open up new avenues for investigating exotic phases of matter. A driven-dissipative frustrated spin system is examined in this study, and we suggest an out-of-equilibrium non-magnetic phase where the spins do not order but adhere to the ice rule in space and establish a long-range crystalline order in time. In contrast to the conventional spin ice, the dynam…
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Studies on systems far from equilibrium open up new avenues for investigating exotic phases of matter. A driven-dissipative frustrated spin system is examined in this study, and we suggest an out-of-equilibrium non-magnetic phase where the spins do not order but adhere to the ice rule in space and establish a long-range crystalline order in time. In contrast to the conventional spin ice, the dynamics of monopoles is confined due to the nonequilibrium feature of our model. Possible experimental realizations of our model has been discussed.
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Submitted 18 July, 2023; v1 submitted 8 January, 2023;
originally announced January 2023.
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Space-time symmetry breaking in nonequilibrium frustrated magnetism
Authors:
Mingxi Yue,
Zi Cai
Abstract:
Spontaneous symmetry breaking is responsible for the rich phenomena in equilibrium physics. Driving a system out-of-equilibrium can significantly enrich the possibility of spontaneous symmetry breaking, which occurs not only in space, but also in time domain. This study investigates a driven-dissipative frustrated magnetic system. Results show that frustration in such a far-from-equilibrium system…
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Spontaneous symmetry breaking is responsible for the rich phenomena in equilibrium physics. Driving a system out-of-equilibrium can significantly enrich the possibility of spontaneous symmetry breaking, which occurs not only in space, but also in time domain. This study investigates a driven-dissipative frustrated magnetic system. Results show that frustration in such a far-from-equilibrium system could lead to a wealth of intriguing non-equilibrium phases with intertwined space-time symmetry breaking, (e.g.) a discrete time crystal phase accompanied by a time-dependent spatial order oscillating between a long-range tripartite stripe and a short-range ferromagnetic order.
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Submitted 8 January, 2023; v1 submitted 29 September, 2022;
originally announced September 2022.
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Layer-dependent interlayer antiferromagnetic spin reorientation in air-stable semiconductor CrSBr
Authors:
Chen Ye,
Cong Wang,
Qiong Wu,
Sheng Liu,
Jiayuan Zhou,
Guopeng Wang,
Aljoscha Soll,
Zdenek Sofer,
Ming Yue,
Xue Liu,
Mingliang Tian,
Qihua Xiong,
Wei Ji,
X. Renshaw Wang
Abstract:
Magnetic van der Waals (vdW) materials offer a fantastic platform to investigate and exploit rich spin configurations stabilized in reduced dimensions. One tantalizing magnetic order is the interlayer antiferromagnetism in A-type vdW antiferromagnet, which may be effectively modified by the magnetic field, stacking order and thickness scaling. However, atomically revealing the interlayer spin orie…
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Magnetic van der Waals (vdW) materials offer a fantastic platform to investigate and exploit rich spin configurations stabilized in reduced dimensions. One tantalizing magnetic order is the interlayer antiferromagnetism in A-type vdW antiferromagnet, which may be effectively modified by the magnetic field, stacking order and thickness scaling. However, atomically revealing the interlayer spin orientation in the vdW antiferromagnet is highly challenging, because most of the material candidates exhibit an insulating ground state or instability in ambient conditions. Here, we report the layer-dependent interlayer antiferromagnetic reorientation in air-stable semiconductor CrSBr using magnetotransport characterization and first-principles calculations. We reveal a pronounced odd-even layer effect of interlayer reorientation, which originates from the competitions among interlayer exchange, magnetic anisotropy energy and extra Zeeman energy of uncompensated magnetization. Furthermore, we quantitatively constructed the layer-dependent magnetic phase diagram with the help of a linear-chain model. Our work uncovers the layer-dependent interlayer antiferromagnetic reorientation engineered by magnetic field in the air-stable semiconductor, which could contribute to future vdW spintronic devices.
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Submitted 20 May, 2022; v1 submitted 11 May, 2022;
originally announced May 2022.
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Thermal melting of discrete time crystals: a dynamical phase transition induced by thermal fluctuations
Authors:
Mingxi Yue,
Xiaoqin Yang,
Zi Cai
Abstract:
The stability of a discrete time crystal against thermal fluctuations has been studied numerically by solving a stochastic Landau-Lifshitz-Gilbert equation of a periodically-driven classical system composed of interacting spins, each of which couples to a thermal bath. It is shown that in the thermodynamic limit, even though the long-range temporary crystalline order is stable at low temperature,…
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The stability of a discrete time crystal against thermal fluctuations has been studied numerically by solving a stochastic Landau-Lifshitz-Gilbert equation of a periodically-driven classical system composed of interacting spins, each of which couples to a thermal bath. It is shown that in the thermodynamic limit, even though the long-range temporary crystalline order is stable at low temperature, it is melting above a critical temperature, at which the system experiences a non-equilibrium phase transition. The critical behaviors of the continuous phase transition have been systematically investigated, and it is shown that despite the genuine non-equilibrium feature of such a periodically driven system, its critical properties fall into the 3D Ising universality class with a dynamical exponent ($z=2$) identical to that in the critical dynamics of kinetic Ising model without driving.
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Submitted 22 March, 2022; v1 submitted 28 October, 2021;
originally announced October 2021.
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Order by disorder in frustration-free systems: a Quantum Monte Carlo study of a two-dimensional PXP model
Authors:
Mingxi Yue,
Zijian Wang,
Bhaskar Mukherjee,
Zi Cai
Abstract:
In this study, an order by disorder mechanism has been proposed in a two-dimensional PXP model, where the extensive degeneracy of the classical ground-state manifold is due to strict occupation constraints instead of geometrical frustrations. By performing an unbias large-scale quantum monte carlos simulation, we find that local quantum fluctuations, which usually work against long-range ordering,…
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In this study, an order by disorder mechanism has been proposed in a two-dimensional PXP model, where the extensive degeneracy of the classical ground-state manifold is due to strict occupation constraints instead of geometrical frustrations. By performing an unbias large-scale quantum monte carlos simulation, we find that local quantum fluctuations, which usually work against long-range ordering, lift the macroscopic classical degeneracy and give rise to a compressible ground state with charge-density-wave long-range order. A simple trial wavefunction has been proposed to capture the essence of the ground-state of the two-dimensional PXP model. The finite temperature properties of this model have also been studied, and we find a thermal phase transition with an universality class of two-dimensional Ising model.
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Submitted 18 May, 2021; v1 submitted 28 March, 2021;
originally announced March 2021.
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Effects of Surface Trapping and Contact Ion Pairing on Ion Transport in Nanopores
Authors:
Zhongwu Li,
Yinghua Qiu,
Yan Zhang,
Min Yue,
Yunfei Chen
Abstract:
Ion transport in highly-confined space is important to various applications, such as biosensing and seawater desalination with nanopores. All-atom molecular dynamics simulations are conducted to investigate the transport of Na$^+$ and Cl$^-$ ions through nanopores with the diameter below 6 nm. It is found that the formation of the contact ion pair plays a critical role in reducing the ion mobility…
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Ion transport in highly-confined space is important to various applications, such as biosensing and seawater desalination with nanopores. All-atom molecular dynamics simulations are conducted to investigate the transport of Na$^+$ and Cl$^-$ ions through nanopores with the diameter below 6 nm. It is found that the formation of the contact ion pair plays a critical role in reducing the ion mobility inside a nanopore without surface charges. The mobility for both cations and anions decreases with the reduced pore size because it is easier to form the contact ion pairs inside the neutral nanopore with smaller diameter. Inside a charged nanopores, besides the contact ion pair formation, the surface charges also play a significant role in reducing the counterion mobility through surface trapping. It is uncovered that the mobility of Na$^+$ ions increases first and then decreases with the surface charge density, while Cl$^-$ ions have the opposite trend. A modified first-passage time model is proposed to take into account the ion pair formation and the trapped ions inside a nanopore, which provides a clear picture in describing ion transport through a nanopore.
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Submitted 27 July, 2019;
originally announced July 2019.
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Magnetization flip in Fe-Cr-Ga system
Authors:
H. G. Zhang,
B. T Song,
J. Chen,
M. Yue,
E. K. Liu,
W. H. Wang,
G. H. Wu
Abstract:
A systematic investigation about the structure and magnetism of Fe75-xCr25Gax (11<x<33) and Fe50Cr50-yGay (0<y<33) series has been carried out in this work. It shows that the parent Fe50Cr25Ga25 phase has higher tolerance for Ga replacing Cr than replacing Fe atoms. An abrupt flip of Curie temperature and magnetization in the Fe50Cr50-yGay (0<y<33) series was observed at the composition of Fe50Cr2…
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A systematic investigation about the structure and magnetism of Fe75-xCr25Gax (11<x<33) and Fe50Cr50-yGay (0<y<33) series has been carried out in this work. It shows that the parent Fe50Cr25Ga25 phase has higher tolerance for Ga replacing Cr than replacing Fe atoms. An abrupt flip of Curie temperature and magnetization in the Fe50Cr50-yGay (0<y<33) series was observed at the composition of Fe50Cr25Ga25. We proposed an explanation concerning anti-sites occupation and magnetic structure transition in this series. The induced structure is proved energetically favorable from first-principles calculations. This work can help us to understand the dependences between the crystal structure and magnetism in Fe-based Heusler compounds, and provides a method to deduce the atomic configurations based on the evolution of magnetism.
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Submitted 29 December, 2018;
originally announced December 2018.
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Windows open for highly tunable magnetostructural phase transitions
Authors:
Y. Li,
Z. Y. Wei,
H. G. Zhang,
E. K. Liu,
H. Z. Luo,
G. D. Liu,
X. K. Xi,
S. G. Wang,
W. H. Wang,
M. Yue,
G. H. Wu,
X. X. Zhang
Abstract:
An attempt was made to tailor the magnetostructural transitions (MSTs) over a wide temperature range under the principle of isostructural alloying. A series of wide Curie-temperature windows (CTWs) with a maximal width of 377 K between 69 and 446 K were established in the Mn1-yCoyNiGe1-xSix system. Throughout the CTWs, the magnetic-field-induced metamagnetic behavior and giant magnetocaloric effec…
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An attempt was made to tailor the magnetostructural transitions (MSTs) over a wide temperature range under the principle of isostructural alloying. A series of wide Curie-temperature windows (CTWs) with a maximal width of 377 K between 69 and 446 K were established in the Mn1-yCoyNiGe1-xSix system. Throughout the CTWs, the magnetic-field-induced metamagnetic behavior and giant magnetocaloric effects are obtained. The (Mn,Co)Ni(Ge,Si) system shows great potential as multifunctional phase-transition materials that work in a wide range covering liquid-nitrogen and above water-boiling temperatures. Moreover, general understanding to isostructural alloying and CTWs constructed in (Mn,Co)Ni(Ge,Si) as well as (Mn,Fe)Ni(Ge,Si) are provided.
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Submitted 18 July, 2016;
originally announced July 2016.
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Anti-sites disordering suppression of the possible phase transition in Mn2CrGa
Authors:
H. G. Zhang,
J. Chen,
E. K. Liu,
M. Yue,
Q. M. Lu,
W. H. Wang,
G. H. Wu
Abstract:
Theoretical and experimental characterizations of Mn2CrGa compound in regard to the possibility of phase transformation have been carried out in this work. Under a high ordering L21 structure, this compound has the potential to be a martensite phase transition material. However, experimental results show a severe disordering took place in this system, which forbids the occurring of the phase trans…
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Theoretical and experimental characterizations of Mn2CrGa compound in regard to the possibility of phase transformation have been carried out in this work. Under a high ordering L21 structure, this compound has the potential to be a martensite phase transition material. However, experimental results show a severe disordering took place in this system, which forbids the occurring of the phase transition. This work provides important reference for the design of new phase transition materials in Heusler alloys.
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Submitted 1 February, 2016;
originally announced February 2016.
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Preparation, structure evolution, and magnetocaloric effects of MnFe(PGe) compounds
Authors:
Ming Yue,
Hongguo Zhang,
Danmin Liu,
Jiuxing Zhang
Abstract:
As one of magnetic refrigerants with giant magnetocaloric effect (GMCE), MnFePGe-based compounds had drawn tremendous attention due to their many advantages for practical applications. In this paper, correlations among preparation conditions, magnetic and crystal structures, and magnetocaloric effects (MCE) of the MnFePGe-based compounds are reviewed. Structure evolution and phase transformation i…
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As one of magnetic refrigerants with giant magnetocaloric effect (GMCE), MnFePGe-based compounds had drawn tremendous attention due to their many advantages for practical applications. In this paper, correlations among preparation conditions, magnetic and crystal structures, and magnetocaloric effects (MCE) of the MnFePGe-based compounds are reviewed. Structure evolution and phase transformation in the compounds as a function of temperature, pressure, and magnetic field were reported. Influences of preparation conditions to the chemical composition and microstructure homogeneity of the compounds, which play key role to the MCE and thermal hysteresis of the compounds, were introduced. Based upon these experimental results, a new method to evaluate MCE of the compounds via DSC measurements was proposed. Moreover, the origin of virgin effect of the MnFePGe-based compounds was discussed.
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Submitted 13 November, 2014;
originally announced November 2014.
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A pathway to optimize the properties of magnetocaloric MnxFe2-x(P1-yGey) for magnetic refrigeration
Authors:
D. M. Liu,
Z. L. Zhang,
S. L. Zhou,
Q. Z. Huang,
X. J. Deng,
M. Yue,
C. X. Liu,
F. X. Hu,
G. H. Rao,
B. G. Shen,
J. X. Zhang,
J. W. Lynn
Abstract:
Magnetocaloric materials can be useful in magnetic refrigeration applications, but to be practical the magneto-refrigerant needs to have a very large magnetocaloric effect (MCE) near room temperature for modest applied fields (<2 Tesla) with small hysteresis and magnetostriction, and should have a complete magnetic transition, be inexpensive, and environmentally friendly. One system that may fulfi…
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Magnetocaloric materials can be useful in magnetic refrigeration applications, but to be practical the magneto-refrigerant needs to have a very large magnetocaloric effect (MCE) near room temperature for modest applied fields (<2 Tesla) with small hysteresis and magnetostriction, and should have a complete magnetic transition, be inexpensive, and environmentally friendly. One system that may fulfill these requirements is MnxFe2-xP1-yGey, where a combined first-order structural and magnetic transition occurs between the high temperature paramagnetic and low temperature ferromagnetic phase. We have used neutron diffraction, differential scanning calorimetry, and magnetization measurements to study the effects of Mn and Ge location in the structure on the ordered magnetic moment, MCE, and hysteresis for a series of compositions of the system near optimal doping. The diffraction results indicate that the Mn ions located on the 3f site enhance the desirable properties, while those located on the 3g sites are detrimental. The entropy changes measured directly by calorimetry can exceed 40 J/kg-K. The phase fraction that transforms, hysteresis of the transition, and entropy change can be controlled by both the compositional homogeneity and the particle size, and an annealing procedure has been developed that substantially improves the performance of all three properties of the material. On the basis of these results we have identified a pathway to optimize the MCE properties of this system for magnetic refrigeration applications.
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Submitted 28 August, 2014;
originally announced August 2014.
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Temperature, magnetic field, and pressure dependence of the crystal and magnetic structures of the magnetocaloric compound Mn1.1Fe0.9(P0.8Ge0.2)
Authors:
D. M. Liu,
Q. Huang,
M. Yue,
J. W. Lynn,
L. J. Liu,
Y. Chen,
Z. H. Wu,
J. X. Zhang
Abstract:
Neutron powder diffraction studies of the crystal and magnetic structures of the magnetocaloric compound Mn1.1Fe0.9(P0.8Ge0.2) have been carried out as a function of temperature, applied magnetic field, and pressure. The data reveal that there is only one transition observed over the entire range of variables explored, which is a combined magnetic and structural transformation between the parama…
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Neutron powder diffraction studies of the crystal and magnetic structures of the magnetocaloric compound Mn1.1Fe0.9(P0.8Ge0.2) have been carried out as a function of temperature, applied magnetic field, and pressure. The data reveal that there is only one transition observed over the entire range of variables explored, which is a combined magnetic and structural transformation between the paramagnetic to ferromagnetic phases (Tc~255 K for this composition). The structural part of the transition is associated with an expansion of the hexagonal unit cell in the direction of the a- and b-axes and a contraction of the c-axis as the FM phase is formed, which originates from an increase in the intra-layer metal-metal bond distance. The application of pressure is found to have an adverse effect on the formation of the FM phase since pressure opposes the expansion of the lattice and hence decreases Tc. The application of a magnetic field, on the other hand, has the expected effect of enhancing the FM phase and increasing Tc. We find that the substantial range of temperature/field/pressure coexistence of the PM and FM phases observed is due to compositional variations in the sample. In-situ high temperature diffraction measurements were carried out to explore this issue, and reveal a coexisting liquid phase at high temperatures that is the origin of this variation. We show that this range of coexisting phases can be substantially reduced by appropriate heat treatment to improve the sample homogeneity.
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Submitted 16 July, 2009; v1 submitted 27 April, 2009;
originally announced April 2009.