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Terahertz optical activity near crystal field transitions of Tm3+ ions in magnetoelectric alumoborates
Authors:
A. M. Kuzmenko,
V. Yu. Ivanov,
S. V. Garnov,
A. Shuvaev,
A. Pimenov,
K. N. Boldyrev,
I. A. Gudim,
A. A. Mukhin
Abstract:
Crystal field (CF) excitations in the ground multiplet $^3H_6$ of Tm$^{3+}$ ions were investigated using terahertz transmission spectra of magnetoelectric TmAl$_3$(BO$_3$)$_4$ and Tm$_{0.05}$Yb$_{0.1}$Y$_{0.85}$Al$_3$(BO$_3$)$_4$. These excitations were identified as mainly magnetic dipole transitions from the ground singlet A$_1$ to the next excited doublet E, split by the crystal field of the D…
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Crystal field (CF) excitations in the ground multiplet $^3H_6$ of Tm$^{3+}$ ions were investigated using terahertz transmission spectra of magnetoelectric TmAl$_3$(BO$_3$)$_4$ and Tm$_{0.05}$Yb$_{0.1}$Y$_{0.85}$Al$_3$(BO$_3$)$_4$. These excitations were identified as mainly magnetic dipole transitions from the ground singlet A$_1$ to the next excited doublet E, split by the crystal field of the D$_3$ symmetry. The fine structure of the modes was resolved at low temperatures. It manifested differently in lightly doped and in pure Tm borates, consistent with different distortions of the local crystal field with the D$_3$ symmetry. Strong natural optical activity was observed near the CF transitions resulting in a polarization plane rotation up to 25 degrees. The optical activity is quantitatively described by contributions of magnetic and electric dipole transitions to dynamic magnetoelectric susceptibility and taking into account the classification of local distortions.
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Submitted 2 April, 2026;
originally announced April 2026.
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First-Order Spin-Reorientation Transition and Incomplete Softening of the Antiferromagnetic Resonance Mode in Multiferroic GdFe$_3$(BO$_3$)$_4$
Authors:
I. N. Khoroshiy,
S. A. Skorobogatov,
S. E. Nikitin,
I. A. Gudim,
V. R. Titova,
A. I. Pankrats
Abstract:
The multiferroic ferroborate GdFe$_3$(BO$_3$)$_4$ with huntite-type structure exhibits magnetic ordering below T$_N$ = 38 K and contains two magnetic subsystems associated with Gd and Fe ions. Competing anisotropies of these subsystems drive a spin reorientation transition at T$_{SR}$ = 10.7 K, switching the ground state from easy-axis to easy-plane. Using antiferromagnetic resonance, we investiga…
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The multiferroic ferroborate GdFe$_3$(BO$_3$)$_4$ with huntite-type structure exhibits magnetic ordering below T$_N$ = 38 K and contains two magnetic subsystems associated with Gd and Fe ions. Competing anisotropies of these subsystems drive a spin reorientation transition at T$_{SR}$ = 10.7 K, switching the ground state from easy-axis to easy-plane. Using antiferromagnetic resonance, we investigate the spin dynamics across this transition. The observed incomplete softening of a magnon mode during both field- and temperature-induced spin-reorientation transitions indicates the first-order nature of the phase transition, which is accompanied by a discontinuous jump in the effective anisotropy field. We reproduce this behavior using a simple model that attributes the jump in the anisotropy field to the presence of an effective fourth-order anisotropy constant, responsible for the discontinuous character of the transition. Remarkably, for in-plane magnetic fields, we identify a new AFMR mode that persists from 12 K up to T$_N$. This mode likely corresponds to the dynamics of a long period incommensurate state, previously detected by resonant elastic X-ray scattering.
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Submitted 31 October, 2025;
originally announced October 2025.
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Features of synthesis of TbCr$_3$(BO$_3$)$_4$ single crystals by solution-melt method
Authors:
I. A. Gudim,
N. V. Mikhashenok
Abstract:
The phase formation of terbium chromium borate in melt solutions based on bismuth trimolybdate and lithium tungstate was studied. It was shown that there is no trigonal phase of terbium chromium borate in a system based on bismuth trimolybdate at all component ratios. The ratio of components of a system based on lithium tungstate has been found, at which trigonal TbCr$_3$(BO$_3$)$_4$ crystals are…
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The phase formation of terbium chromium borate in melt solutions based on bismuth trimolybdate and lithium tungstate was studied. It was shown that there is no trigonal phase of terbium chromium borate in a system based on bismuth trimolybdate at all component ratios. The ratio of components of a system based on lithium tungstate has been found, at which trigonal TbCr$_3$(BO$_3$)$_4$ crystals are formed at temperatures above 1100$^\circ$C, and below this temperature only a monoclinic phase is formed. The X-ray properties of the grown crystals were studied.
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Submitted 11 December, 2023;
originally announced December 2023.
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Quantum versus classical nature of a low-temperature magnetic phase transition in TbAl$_3$(BO$_3$)$_4$
Authors:
T. Zajarniuk,
A. Szewczyk,
P. Wisniewski,
M. U. Gutowska,
R. Puzniak,
H. Szymczak,
I. Gudim,
V. A. Bedarev,
M. I. Pashchenko,
P. Tomczak,
W. Szuszkiewicz
Abstract:
Specific heat, $C_B$, of a TbAl$_3$(BO$_3$)$_4$ crystal was studied for 50 mK $<T<$ 300 K, with emphasis on $T<1$ K, where a phase transition was found at $T_c =0.68$ K. Nuclear, non-phonon ($C_m$), and lattice contributions to $C_B$ were separated. Lowering of $T_c$ with ncrease of magnetic field parallel to the easy magnetization axis, $B_{||}$, was found. It was established that $C_m$ and a Grü…
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Specific heat, $C_B$, of a TbAl$_3$(BO$_3$)$_4$ crystal was studied for 50 mK $<T<$ 300 K, with emphasis on $T<1$ K, where a phase transition was found at $T_c =0.68$ K. Nuclear, non-phonon ($C_m$), and lattice contributions to $C_B$ were separated. Lowering of $T_c$ with ncrease of magnetic field parallel to the easy magnetization axis, $B_{||}$, was found. It was established that $C_m$ and a Grüneisen ratio depend on $B_{||}$ and $T$ in a way characteristic of systems, in which a classical transition is driven by quantum fluctuations, QF, to a quantum critical point at $T=0$, by tuning a control parameter ($B_{||}$). The $B_{||} - T$ phase diagram was constructed and the dynamical critical exponent $0.82 \le z \le 0.96$ was assessed. Nature of the transition was not established explicitly. Magnetization studies point at the ferromagnetic ordering of Tb$^{3+}$ magnetic moments, however, lowering of $T_c$ with increase in $B_{||}$ is opposite to the classical behavior. Hence, a dominant role of QF was supposed.
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Submitted 28 April, 2022;
originally announced April 2022.
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Low-Temperature Magnetic Susceptibility of Erbium Aluminum Borate Single Crystal: Van Vleck Paramagnetism and Spin Correlations
Authors:
D. N. Merenkov,
V. A. Bedarev,
S. N. Poperezhai,
Yu. A. Savina,
T. Zajarniuk,
A. Szewczyk,
I. A. Gudim
Abstract:
Temperature dependencies of magnetic susceptibility in a trigonal single crystal of erbium aluminum borate were measured in the temperature range of 2 - 15 K at the external field of 100 Oe applied along the second- and third-order crystallographic axes. Analysis of the experimental data allows to identify the Van Vleck contribution to the susceptibility. The influence of spin correlations on the…
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Temperature dependencies of magnetic susceptibility in a trigonal single crystal of erbium aluminum borate were measured in the temperature range of 2 - 15 K at the external field of 100 Oe applied along the second- and third-order crystallographic axes. Analysis of the experimental data allows to identify the Van Vleck contribution to the susceptibility. The influence of spin correlations on the magnetic susceptibility has been identified. It has been estimate the negative paramagnetic Curie-Weiss temperature.
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Submitted 14 February, 2022; v1 submitted 16 November, 2021;
originally announced November 2021.
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Probing Magnetic Sublattices in Multiferroic Ho$_{0.5}$Nd$_{0.5}$Fe$_{3}$(BO$_{3}$)$_{4}$ Single Crystal using X-ray Magnetic Circular Dichroism
Authors:
Mikhail Platunov,
Natalia Kazak,
Viacheslav Dudnikov,
Fabrice Wilhelm,
Amir Hen,
Vadim Diadkin,
Iurii Dovgaliuk,
Alexey Bosak,
Vladislav Temerov,
Irina Gudim,
Yurii Knyazev,
Sergey Gavrilkin,
Andrei Rogalev,
Sergei Ovchinnikov
Abstract:
Using element-specific X-ray magnetic circular dichroism (XMCD) technique we have studied different magnetic sublattices in a multiferroic Ho$_{0.5}$Nd$_{0.5}$Fe$_{3}$(BO$_{3}$)$_{4}$ single crystal. The XMCD measurements at the \emph{L}$_{2,3}$-edges of Ho and Nd, and at the Fe \emph{K}-edge have been performed at \emph{T}=2~K under a magnetic field up to 17~T applied along the trigonal \emph{c}-…
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Using element-specific X-ray magnetic circular dichroism (XMCD) technique we have studied different magnetic sublattices in a multiferroic Ho$_{0.5}$Nd$_{0.5}$Fe$_{3}$(BO$_{3}$)$_{4}$ single crystal. The XMCD measurements at the \emph{L}$_{2,3}$-edges of Ho and Nd, and at the Fe \emph{K}-edge have been performed at \emph{T}=2~K under a magnetic field up to 17~T applied along the trigonal \emph{c}-axis as well as in the basal \emph{ab}-plane. All three magnetic sublattices are shown to undergo a spin-reorientation transition under magnetic field applied along the \emph{c}-axis. On the contrary, when magnetic field is applied in the \emph{ab}-plane only the holmium atoms exhibit a magnetization jump. Thus, the element-specific magnetization curves revealed the Ho sublattice to be much stronger coupled to the Fe one than the Nd sublattice. The results demonstrate that the Ho$^{3+}$ subsystem plays even more dominant role in magnetic behavior of Ho$_{0.5}$Nd$_{0.5}$Fe$_{3}$(BO$_{3}$)$_{4}$ crystal than in pure HoFe$_{3}$(BO$_{3}$)$_{4}$ crystal.
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Submitted 19 April, 2018;
originally announced April 2018.
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Switching of magnons by electric and magnetic fields in multiferroic borates
Authors:
A. M. Kuzmenko,
D. Szaller,
Th. Kain,
V. Dziom,
L. Weymann,
A. Shuvaev,
Anna Pimenov,
A. A. Mukhin,
V. Yu. Ivanov,
I. A. Gudim,
L. N. Bezmaternykh,
A. Pimenov
Abstract:
Electric manipulation of magnetic properties is a key problem of materials research. To fulfil the requirements of modern electronics, these processes must be shifted to high frequencies. In multiferroic materials this may be achieved by electric and magnetic control of their fundamental excitations. Here we identify magnetic vibrations in multiferroic iron-borates which are simultaneously sensiti…
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Electric manipulation of magnetic properties is a key problem of materials research. To fulfil the requirements of modern electronics, these processes must be shifted to high frequencies. In multiferroic materials this may be achieved by electric and magnetic control of their fundamental excitations. Here we identify magnetic vibrations in multiferroic iron-borates which are simultaneously sensitive to external electric and magnetic fields. Nearly 100% modulation of the terahertz radiation in an external field is demonstrated for SmFe3(BO3)4. High sensitivity can be explained by a modification of the spin orientation which controls the excitation conditions in multiferroic borates. These experiments demonstrate the possibility to alter terahertz magnetic properties of materials independently by external electric and magnetic fields.
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Submitted 10 December, 2017;
originally announced December 2017.
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Terahertz spectroscopy of crystal-field transitions in magnetoelectric TmAl3(BO3)4
Authors:
A. M. Kuzmenko,
A. A. Mukhin,
V. Vu. Ivanov,
G. A. Komandin,
A. Shuvaev,
A. Pimenov,
V. Dziom,
L. N. Bezmaternykh,
I. A. Gudim
Abstract:
Dynamic magnetic properties of magnetoelectric TmAl3(BO3)4 borate have been investigated by terahertz spectroscopy. Crystal field (CF) transitions within the ground multiplet 3H6 of Tm3+ ions are observed and they are identified as magnetic-dipole transitions from the ground singlet A1 to the next excited doublet E of Tm3+ ions. Unexpected fine structure of the transitions is detected at low tempe…
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Dynamic magnetic properties of magnetoelectric TmAl3(BO3)4 borate have been investigated by terahertz spectroscopy. Crystal field (CF) transitions within the ground multiplet 3H6 of Tm3+ ions are observed and they are identified as magnetic-dipole transitions from the ground singlet A1 to the next excited doublet E of Tm3+ ions. Unexpected fine structure of the transitions is detected at low temperatures. The new modes are assigned to local distortions of the sites with D3 symmetry by Bi3+ impurities, which resulted in the splitting of A1 -> E transition. Two types of locally distorted sites are identified and investigated. The main contribution to the static magnetic susceptibility is shown to be determined by the matrix elements of the observed magnetic transitions. We demonstrate that even in case of local distortions the symmetry of the undistorted crystal is recovered for magnetic and for quadratic magnetoelectric susceptibilities.
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Submitted 7 April, 2017;
originally announced April 2017.
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Spectroscopy of f-f transitions, crystal-field calculations, and magnetic and quadrupole helix chirality in DyFe$_3$(BO$_3$)$_4$
Authors:
M. N. Popova,
E. P. Chukalina,
K. N. Boldyrev,
T. N. Stanislavchuk,
B. Z. Malkin,
I. A. Gudim
Abstract:
Recently, quadrupole helix chirality and its domain structure was observed in resonant x-ray diffraction experiments on DyFe$_3$(BO$_3$)$_4$ using circularly polarized x rays [T. Usui et al., Nature Materials 13, 611 (2014)]. We show that this effect can be explained quantitatively by calculating the quadrupole moments of the Dy$^{3+}$ ions induced by the low-symmetry ($C_2$) crystal-field (CF) co…
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Recently, quadrupole helix chirality and its domain structure was observed in resonant x-ray diffraction experiments on DyFe$_3$(BO$_3$)$_4$ using circularly polarized x rays [T. Usui et al., Nature Materials 13, 611 (2014)]. We show that this effect can be explained quantitatively by calculating the quadrupole moments of the Dy$^{3+}$ ions induced by the low-symmetry ($C_2$) crystal-field (CF) component. In this work, the CF parameters for the Dy$^{3+}$ ions in the $P3_121$ ($P3_221$) phase of DyFe$_3$(BO$_3$)$_4$ are obtained from CF calculations based on the analysis of high-resolution temperature-dependent optical spectroscopy data. We also consider the helix chirality of the single-site magnetic susceptibility tensors of the Dy$^{3+}$ ions in the paramagnetic $P3_121$ ($P3_221$) phase and suggest a neutron diffraction experiment to reveal it.
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Submitted 23 November, 2016; v1 submitted 21 November, 2016;
originally announced November 2016.
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Temperature- and Magnetic-Field-Tuning of Magnetic Phases in Multiferroic NdFe3(BO3)4
Authors:
Christie S. Nelson,
Leonard N. Bezmaternykh,
Irina A. Gudim
Abstract:
We report the low-temperature coexistence in NdFe3(BO3)4 of an incommensurate magnetic phase with a strained commensurate magnetic phase that is primarily at the surface of the crystal. Increasing the temperature or magnetic field decreases the incommensurability and stabilizes the commensurate magnetic phase above Tic ~14 K or Hic = 0.9 T. A comparison to published studies indicates the onset of…
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We report the low-temperature coexistence in NdFe3(BO3)4 of an incommensurate magnetic phase with a strained commensurate magnetic phase that is primarily at the surface of the crystal. Increasing the temperature or magnetic field decreases the incommensurability and stabilizes the commensurate magnetic phase above Tic ~14 K or Hic = 0.9 T. A comparison to published studies indicates the onset of longitudinal magnetostriction and electric polarization at the magnetic-field-induced transition, which may arise due to a basal plane spin-flop and canting of the moments along the field direction.
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Submitted 13 June, 2013;
originally announced June 2013.
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Ho and Fe magnetic ordering in multiferroic HoFe3(BO3)O4
Authors:
D. K. Shukla,
S. Francoual,
A. Skaugen,
M. v. Zimmermann,
H. C. Walker,
L. N. Bezmaternykh,
I. A. Gudim,
V. L. Temerov,
J. Strempfer
Abstract:
Resonant and non-resonant X-ray scattering studies on HoFe3(BO3)O4 reveal competing magnetic ordering of Ho and Fe moments. Temperature and X-ray polarization dependent measurements employed at the Ho L3 edge directly reveal a spiral spin order of the induced Ho moments in the ab-plane propagating along the c-axis, a screw-type magnetic structure. At about 22.5 K the Fe spins are observed to rotat…
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Resonant and non-resonant X-ray scattering studies on HoFe3(BO3)O4 reveal competing magnetic ordering of Ho and Fe moments. Temperature and X-ray polarization dependent measurements employed at the Ho L3 edge directly reveal a spiral spin order of the induced Ho moments in the ab-plane propagating along the c-axis, a screw-type magnetic structure. At about 22.5 K the Fe spins are observed to rotate within the basal plane inducing spontaneous electric polarization, P. Components of P in the basal plane and along the c-axis can be scaled with the separated magnetic X-ray scattering intensities of the Fe and Ho magnetic sublattices, respectively.
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Submitted 4 April, 2013;
originally announced April 2013.
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Magnetoelectricity in the system $RAl_3(BO_3)_4$ ($R$ = Tb, Ho, Er, Tm)
Authors:
K. -C. Liang,
R. P. Chaudhury,
B. Lorenz,
Y. Y. Sun,
L. N. Bezmaternykh,
I. A. Gudim,
V. L. Temerov,
C. W. Chu
Abstract:
The magnetoelectric effect in the system $RAl_3(BO_3)_4$ ($R$ = Tb, Ho, Er, Tm) is investigated between 3 K and room temperature and at magnetic fields up to 70 kOe. We show a systematic increase of the magnetoelectric effect with decreasing magnetic anisotropy of the rare earth moment. A giant magnetoelectric polarization is found in the magnetically (nearly) isotropic $HoAl_3(BO_3)_4$. The polar…
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The magnetoelectric effect in the system $RAl_3(BO_3)_4$ ($R$ = Tb, Ho, Er, Tm) is investigated between 3 K and room temperature and at magnetic fields up to 70 kOe. We show a systematic increase of the magnetoelectric effect with decreasing magnetic anisotropy of the rare earth moment. A giant magnetoelectric polarization is found in the magnetically (nearly) isotropic $HoAl_3(BO_3)_4$. The polarization value in transverse field geometry at 70 kOe reaches 3600 $μC/m^2$ which is significantly higher than reported values for the field-induced polarization of linear magnetoelectric or even multiferroic compounds. The results indicate a very strong coupling of the f-moments to the lattice. They further indicate the importance of the field-induced ionic displacements in the unit cell resulting in a polar distortion and a change in symmetry on a microscopic scale. The system $RAl_3(BO_3)_4$ could be interesting for the technological utilization of the high-field magnetoelectric effect.
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Submitted 23 January, 2012;
originally announced January 2012.
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Magnetic Phase Transitions in the NdFe_3(BO_3)_4 multiferroic
Authors:
G. A. Zvyagina,
K. R. Zhekov,
I. V. Bilych,
A. A. Zvyagin,
I. A. Gudim,
V. L. Temerov
Abstract:
Low temperature studies of the behavior of the sound velocity and attenuation of acoustic modes have been performed on a single crystal NdFe_3(BO_3)_4. Transitions of the magnetic subsystem to the antiferromagnetically ordered state at T_N \approx 30.6 K have been revealed in the temperature behavior of the elastic characteristics. The features in the temperature behavior of elastic characteristic…
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Low temperature studies of the behavior of the sound velocity and attenuation of acoustic modes have been performed on a single crystal NdFe_3(BO_3)_4. Transitions of the magnetic subsystem to the antiferromagnetically ordered state at T_N \approx 30.6 K have been revealed in the temperature behavior of the elastic characteristics. The features in the temperature behavior of elastic characteristics of the neodymium ferroborate and its behavior in the external magnetic field, applied in the basic plane of the crystal, permit us to suppose that the transition to an incommensurate spiral phase is realized in the system. This phase transition behaves as the first order one. H-T phase diagrams for the cases H \parallel a and H \parallel b have been constructed. The phenomenological theory, which explains observed features, has been developed.
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Submitted 11 April, 2011;
originally announced April 2011.
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Crystal growth and magnetic properties of Nd1-xDyxFe3(BO3)4
Authors:
I. A. Gudim,
E. V. Eremin,
V. L. Temerov
Abstract:
Data about stability areas of Nd1-xDyxFe3(BO3)4 trigonal phases in fluxes on the bismuth trimolibdate basis and feature of labile phase dynamics conditions is noted. Group growth conditions of these phases single crystals on seeds and at spontaneous nucleation in a thin layer of flux on crystal carrier are described. Temperature and field dependences of magnetization and a specific heat for crys…
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Data about stability areas of Nd1-xDyxFe3(BO3)4 trigonal phases in fluxes on the bismuth trimolibdate basis and feature of labile phase dynamics conditions is noted. Group growth conditions of these phases single crystals on seeds and at spontaneous nucleation in a thin layer of flux on crystal carrier are described. Temperature and field dependences of magnetization and a specific heat for crystals with x = 0,1 and x = 0,25 are analyzed. The conclusion, that unlike easy plane NdFe3(BO3)4 antiferromagnetic and easy axis DyFe3(BO3)4 ones, spontaneous spin-flop transitions are inherent in these single crystals is resulted and it is connected with mutual influence of rare-earth subsystems through the common Fe-subsystem with strong exchange interaction. The anisotropies competition exerts essential influence on induced by field H parallel c3 magnetic phase transitions too.
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Submitted 11 June, 2009;
originally announced June 2009.
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Magnetization and specific heat of TbFe3(BO3)4: Experiment and crystal field calculations
Authors:
E. A. Popova,
D. V. Volkov,
A. N. Vasiliev,
A. A. Demidov,
N. P. Kolmakova,
I. A. Gudim,
L. N. Bezmaternykh,
N. Tristan,
Yu. Skourski,
B. Büchner,
C. Hess,
R. Klingeler
Abstract:
We have studied the thermodynamic properties of single-crystalline TbFe3(BO3)4. Magnetization measurements have been carried out as a function of magnetic field (up to 50 T) and temperature up to 350K with the magnetic field both parallel and perpendicular to the trigonal c-axis of the crystal. The specific heat has been measured in the temperature range 2-300K with a magnetic field up to 9 T ap…
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We have studied the thermodynamic properties of single-crystalline TbFe3(BO3)4. Magnetization measurements have been carried out as a function of magnetic field (up to 50 T) and temperature up to 350K with the magnetic field both parallel and perpendicular to the trigonal c-axis of the crystal. The specific heat has been measured in the temperature range 2-300K with a magnetic field up to 9 T applied parallel to the c-axis. The data indicate a structural phase transition at 192 K and antiferromagnetic spin ordering at 40 K. A Schottky anomaly is present in the specific heat data around 20 K, arising due to two low-lying energy levels of the Tb3+ ions being split by f-d coupling. Below TN magnetic fields parallel to the c-axis drive a spin-flop phase transition, which is associated with a large magnetization jump. The highly anisotropic character of the magnetic susceptibility is ascribed mainly to the Ising-like behavior of the Tb3+ ions in the trigonal crystal field. We describe our results in the framework of an unified approach which is based on mean-field approximation and crystal-field calculations.
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Submitted 23 April, 2007;
originally announced April 2007.