Simulation of magnetovolume effects in ferromagnets by a combined molecular dynamics and Monte Carlo approach

Grossmann, B.; Rancourt, Denis

doi:10.1103/physrevb.54.12294

Cited by 17 publications

(10 citation statements)

References 44 publications

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“…An exchange interaction of this form has also been used to describe magneto-volume effects in Fe-Ni Invar. 37,38,39 In this case, the derivative of the exchange constant ∂J ik /∂r was a factor of 2 to 20 larger than in the present work. The values of parameters are summarized in Table III.…”

Section: An Extended Modelcontrasting

confidence: 64%

Instability of the rhodium magnetic moment as the origin of the metamagnetic phase transition inα−FeRh

Gruner¹,

Hoffmann²,

Entel³

2003

Phys. Rev. B

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Based on ab initio total energy calculations we show that two magnetic states of rhodium atoms together with competing ferromagnetic and antiferromagnetic exchange interactions are responsible for a temperature induced metamagnetic phase transition, which experimentally is observed for stoichiometric α-FeRh. Taking into account the results of previous and newly performed firstprinciples calculations we present a spin-based model, which allows to reproduce this first-order metamagnetic transition by means of Monte Carlo simulations. Further inclusion of spacial variation of exchange parameters leads to a realistic description of the experimental magneto-volume effects in α-FeRh.

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Section: An Extended Modelcontrasting

confidence: 64%

Instability of the rhodium magnetic moment as the origin of the metamagnetic phase transition inα−FeRh

Gruner¹,

Hoffmann²,

Entel³

2003

Phys. Rev. B

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“…So, anti-Invar behavior is a direct manifestation of the LM/HM instability but Invar behavior is not. (8) The local moment frustration model (model-G) correctly predicts the influences of chemical order on the magnetic, thermal, and magnetovolume properties of HM FCC Fe-Ni alloys (0-65 apc Fe), with no free parameters Lagarec and Rancourt, 1999;Dang et al, 1995;Dang and Rancourt, 1996;Grossmann and Rancourt, 1996). This represents significant predictive power that no other quantitative model of Invar behavior has achieved.…”

Section: Resultsmentioning

confidence: 93%

“…In a series of papers (Dang et al, 1995;Dang and Rancourt, 1996;Grossmann and Rancourt, 1996) culminating in the description of the local moment frustration model , we have shown by various mean field theory and Monte Carlo calculations that a simple HM local moment model, with fixed moment magnitudes on Fe and Ni, three constant exchange parameters for Fe-Fe, Fe-Ni, and Ni-Ni pairs, and one non-zero constant magnetovolume coupling parameter, J 0 Fe-Fe ¼ @J Fe-Fe =@r, for Fe-Fe pairs, can reproduce the composition and temperature dependencies of all the physical properties of interest: saturation magnetization and deviation from the Slater-Pauling curve, thermal expansion, Curie point, spontaneous volume change, paraprocess high-field magnetic susceptibility, chemical order-disorder effects, bulk modulus, magnetic specific heat, etc. This simple model, with only four adjustable parameters, gives good qualitative agreement and at worst correct orders of magnitudes in the entire range 0 to $ 65 apc Fe and at all relevant temperatures, provided the Fe-Ni and Ni-Ni exchange interactions are relatively large and positive (i.e., ferromagnetic), the Fe-Fe exchange interaction is somewhat smaller and negative (antiferromagnetic), and @J Fe-Fe =@r is large and positive (þ10 4 K/Å , with the Hamiltonian used by Rancourt and Dang (1996)).…”

Section: Local Moment Frustration Model Its Ab Initio Justificationmentioning

confidence: 99%

Invar Behavior in Fe-Ni Alloys is Predominantly a Local Moment Effect Arising from the Magnetic Exchange Interactions Between High Moments

Rancourt

2002

Phase Transitions

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I argue that the main models that have been advanced to explain Invar behavior in Fe-Ni alloys (the original, classical, Invar system) can all be shown to be critically deficient, except one: The local moment frustration model of Rancourt and Dang (Phys. Rev. B, 54, 12225, 1996). The latter model explains all the measured structural, magnetic, and magnetovolume features of the Fe-Ni alloys with 0-65 apc (atomic percent) Fe, based on the assumptions that these systems are predominantly high-moment in character at the temperatures of interest and that the Fe-Fe pairs have large inter-atomic separation dependencies of their magnetic exchange parameters. The large magnetovolume Fe-Fe couplings are understood (based on ab initio electronic structure calculations) as a precursor effect of the low-moment/high-moment (LM/HM) transition that has recently been observed to occur at larger Fe concentrations, as a continuous transition occurring in the range $65-75 apc Fe (Lagarec, Ph.D. thesis, 2001).

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“…Another simulation tackling both spin and lattice subsystems has been carried out by Grossmann and Rancourt, 9 who have performed molecular dynamics (MD) on lattice subsystem and Monte Carlo (MC) simulation on spin subsystem on the basis that lattice vibration is more frequent than that of spin. However, it lacks an explicit treatment of direct coupling between the two subsystems.…”

Section: Introductionmentioning

confidence: 99%

Spin-lattice dynamics simulation of external field effect on magnetic order of ferromagnetic iron

Chui

Zhou

2014

AIP Advances

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Modeling of field-induced magnetization in ferromagnetic materials has been an active topic in the last dozen years, yet a dynamic treatment of distance-dependent exchange integral has been lacking. In view of that, we employ spin-lattice dynamics (SLD) simulations to study the external field effect on magnetic order of ferromagnetic iron. Our results show that an external field can increase the inflection point of the temperature. Also the model provides a better description of the effect of spin correlation in response to an external field than the mean-field theory. An external field has a more prominent effect on the long range magnetic order than on the short range counterpart. Furthermore, an external field allows the magnon dispersion curves and the uniform precession modes to exhibit magnetic order variation from their temperature dependence.

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Simulation of magnetovolume effects in ferromagnets by a combined molecular dynamics and Monte Carlo approach

Cited by 17 publications

References 44 publications

Instability of the rhodium magnetic moment as the origin of the metamagnetic phase transition inα−FeRh

Instability of the rhodium magnetic moment as the origin of the metamagnetic phase transition inα−FeRh

Invar Behavior in Fe-Ni Alloys is Predominantly a Local Moment Effect Arising from the Magnetic Exchange Interactions Between High Moments

Spin-lattice dynamics simulation of external field effect on magnetic order of ferromagnetic iron

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