Reentrant spin-glass state and magnetodielectric effect in the spiral magnet<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Bi</mml:mi><mml:mi>Mn</mml:mi><mml:msub><mml:mi>Fe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:math>

Ghara, Somnath; Jeon, Byeong‐Gyun; Yoo, Kyongjun; Kim, Kee Hoon; Sundaresan, A.

doi:10.1103/physrevb.90.024413

Cited by 72 publications

(38 citation statements)

References 49 publications

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“…However, another way to check whether the present transition is of spin glass type, we have studied freezing temperature T f as a function of frequency. For a typical spin-glass transition, it is characterized by a parameter = ઢ ‫܂‬ ઢ() [12,32,33] , where the value of p should be of the order of 0.01, where T f is the freezing temperature at frequency f. But in the present investigation, the value we obtained is ̴ 0.286 which is much greater than typical p value for spin glass. Therefore, this result confirms that the observed freezing transition is different from typical spin glass transition.…”

Section: (B)contrasting

confidence: 59%

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

Pal

Singh

Ghosh

et al. 2018

Journal of Magnetism and Magnetic Materials

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The magnetization (both dc and ac) of pyrochlore Eu 2 Ti 2 O 7 have been investigated. Ac susceptibility (χ / &χ // ) measurements reveal a new unusual spin freezing below 35K for pure Eu 2 Ti 2 O 7 . Frequency dependence of these ac χ // peak positions indicate slow spin relaxation near this temperature and it follows the Arrhenius formulasuggesting a thermally activated relaxation process. The origin of this spin freezing has been attributed essentially to a single ion process which is associated to Eu 3+ spin relaxation. Non-magnetic dilution by Y 3+ ions also confirms the single ion freezing.

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Section: (B)contrasting

confidence: 59%

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

Pal

Singh

Ghosh

et al. 2018

Journal of Magnetism and Magnetic Materials

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“…14,16,32,40,41 A high value of τ * also points toward the fact that in Cr 0.5 Fe 0.5 Ga, spin dynamics occurs in a slow manner, due to the presence of interacting clusters rather than individual spins. 32,39 No significant change in zν was observed while changing the field from 0 to 0.25 T but the value of τ * is changed by an order of magnitude which is still within the range expected for cluster-SG systems. The presence of interacting clusters is also evident from the failure of Arrhenius law to fit the frequency dependent T f data.…”

Section: Ac Susceptibilitymentioning

confidence: 56%

“…The parameters, τ * and zν are believed to give more reliable insight into the SG dynamics. For conventional SG systems, the value of zν typically lies between ∼ 4 and ∼ 12 while the value of τ * ranges from 10 −10 s to 10 −13 s. 14,16,[38][39][40] Similarly, for the canonical SG and cluster SG, the characteristic range of τ * varies from ∼ 10 −12 s to ∼ 10 −13 s and ∼ 10 −7 to ∼ 10 −10 , respectively. 2,14,32,40,41 Clearly, our obtained values of τ * and zν fall within the ranges reported for typical cluster SG systems.…”

Section: Ac Susceptibilitymentioning

confidence: 99%

Cluster spin-glass behaviour and memory effect in Cr$_{0.5}$Fe$_{0.5}$Ga

Bag,

Baral,

Nath

2018

Preprint

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We report the structural, static, and dynamic properties of Cr0.5Fe0.5Ga by means of powder x-ray diffraction, DC magnetization, heat capacity, AC susceptibility, magnetic relaxation, and magnetic memory effect measurements. DC magnetization and AC susceptibility studies reveal a spin-glass transition at around T f 22 K. An intermediate value of the relative shift in freezing temperature δT f 0.017, obtained from the AC susceptibility data reflects the formation of cluster spin-glass states. The frequency dependence of T f is also analyzed within the framework of dynamic scaling laws such as power law and Vogel-Fulcher law. The analysis using power law yields a characteristic time constant for a single spin flip τ * 1.1 × 10 −10 s and critical exponent zν = 4.2 ± 0.2. On the other hand, the Vogel-Fulcher law yields the characteristic time constant for a single spin flip τ06.6 × 10 −9 s, Vogel-Fulcher temperature T0 = 21.1 ± 0.1 K, and an activation energy Ea/kB 16 K. The value of τ * and τ0 along with a non-zero value of T0 provide further evidence for the cluster spin-glass behaviour. The magnetic field dependent T f follows the de Almeida-Thouless (AT) line with a non-mean-field type instability, reflecting either a different universality class or strong anisotropy in the spin system. A detailed non-equilibrium dynamics study via relaxation and memory effect experiments demonstrates the evolution of the system through a number of intermediate metastable states and striking memory effects. All the above observations render a cluster spin-glass behaviour in Cr0.5Fe0.5Ga which is triggered by magnetic frustration due to competing antiferromagnetic and ferromagnetic interactions and magnetic site disorder. Moreover, the asymmetric response of magnetic relaxation with respect to the change in temperature, below the freezing temperature can be explained by the hierarchical model.

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“…We note that the value of T SG ∼ 25.2 K obtained from T f (H ) versus H 2/3 plot is closer to that obtained from power-law/Vogel-Fulcher spin dynamics. The AT line has been reported for both the canonical SG as well as CSG systems using field dependence of either T irr (H ) [83][84][85] or T f (H ) [30,[86][87][88][89] and represents the boundary between the high-temperature ergodic and low-temperature nonergodic phases. While the original formulation for the AT line was for Ising spins [79], subsequent theoretical papers have shown that it can occur in Heisenberg systems also if the single-ion anisotropy is low and positive [82].…”

Section: Evidence For the Existence Of De Almeida-thouless Line Inmentioning

confidence: 99%

Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2
Kumar
¹
,
Senyshyn
²
,
Pandey
³

2019
Phys. Rev. B
41
7
21
0
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The origin of the spin glass (SG) phase in the well-known multiferroic Pb(Fe 1/2 Nb 1/2)O 3 compound remains controversial due to the complications introduced by the coexistence of SG and long-range ordered (LRO) antiferromagnetic (AFM) phases. We have addressed this controversy through a comprehensive study on a Pb-free system Ca(Fe 1/2 Nb 1/2)O 3 (CFN) which does not exhibit LRO AFM transition. The SG transition in CFN is confirmed by the appearance of a cusp in the temperature dependence of dc magnetization M(T) with a SG freezing temperature T f ∼ 25 K, and bifurcation of the zero-field-cooled and field-cooled magnetization M(T) below the irreversibility temperature T irr ∼ 27 K. Using ac susceptibility [χ (ω, T)] measurements, we show that the spin dynamics follows power/Vogel-Fulcher law-type critical dynamics which diverges at T SG ∼ 24 K with an attempt time τ o ∼ 10 −6 s suggesting cluster spin glass (CSG) behavior. The field dependence of T f (H) and T irr (H) is shown to follow the de Almeida-Thouless line which separates the ergodic and nonergodic phases in the H-T plane and gives T f (H = 0) ∼ 25 K, which is in close agreement with T SG obtained from χ (ω, T). The existence of the glassy phase below T SG is further confirmed by the observation of slow nonexponential decay of thermoremanent magnetization with time, memory and rejuvenation effects, and unidirectional exchange-bias effect in the M-H hysteresis loop of field-cooled samples. The neutron powder-diffraction patterns reveal the absence of any magnetic peak due to LRO AFM phase but show a broad diffuse peak due to the presence of ∼ 2-nm-size AFM spin clusters which are responsible for the CSG freezing in CFN.

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Reentrant spin-glass state and magnetodielectric effect in the spiral magnetBiMnFe2O6

Cited by 72 publications

References 49 publications

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

Cluster spin-glass behaviour and memory effect in Cr$_{0.5}$Fe$_{0.5}$Ga

Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2
Kumar
¹
,
Senyshyn
²
,
Pandey
³

2019
Phys. Rev. B
41
7
21
0
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Reentrant spin-glass state and magnetodielectric effect in the spiral magnetBiMnFe2O6

Cited by 72 publications

References 49 publications

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

High temperature spin-freezing transition in pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

Cluster spin-glass behaviour and memory effect in Cr$_{0.5}$Fe$_{0.5}$Ga

Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2Kumar1, Senyshyn2, Pandey3 2019Phys. Rev. B417210View full textAdd to dashboardCite

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Evidence for cluster spin glass phase with precursor short-range antiferromagnetic correlations in the B -site disordered Ca(Fe1/2
Kumar
¹
,
Senyshyn
²
,
Pandey
³

2019
Phys. Rev. B
41
7
21
0
View full text Add to dashboard Cite