Sound propagation anomalies and phase diagram of chromium alloys

Mitsek, A. I.; Golub, T.V.

doi:10.1134/1.1130996

Cited by 4 publications

(7 citation statements)

References 4 publications

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“…We ignore anisotropies here since we will do the calculation for a spin 1 2 system. We define retarded Green's functions [20,21]…”

Section: The Starting Spin Hamiltonian Iŝmentioning

confidence: 99%

“…Early theories that calculated the effect of magnetoelectric (ME) coupling on the spontaneous magnetization M and electric polarization P in so-called multiferroic materials used a Landau free energy formalism [1,2,3]. All terms in the free energy are written as products of the order parameters M and P and must satisfy the symmetry of the paraphase.…”

Section: Introductionmentioning

confidence: 99%

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Effect of transverse magnetic correlations on a coupled order parameter: Shifted transition temperatures and thermal hysteresis

Livesey

Stamps

2010

Phys. Rev. B

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“…We ignore anisotropies here since we will do the calculation for a spin 1 2 system. We define retarded Green's functions [20,21]…”

Section: The Starting Spin Hamiltonian Iŝmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of transverse magnetic correlations on a coupled order parameter: Shifted transition temperatures and thermal hysteresis

Livesey

Stamps

2010

Phys. Rev. B

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“…47,48 The highest possible coercivity is achieved when antiphase boundaries are planar, and domain wall segments are parallel to them. 49 The antiphase boundaries in CoPt-type magnets often have a preferential crystallographic orientation, which is clear from theoretical considerations, 44 and observed experimentally for CoPt. 39 Typically they slant towards the tetragonal axis, contrary to the domain wall segments which slant away from the tetragonal axis at A c < A ab and d ≪ l cr .…”

Section: Slanting and 'Smart Pinning' Of Domain Walls In Copt-typmentioning

confidence: 93%

Anisotropy of exchange stiffness and its effect on the properties of magnets

Belashchenko

2003

Journal of Magnetism and Magnetic Materials

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Using the spin-spiral formulation of the tight-binding linear muffin-tin orbital method, the principal components of the exchange stiffness tensor are calculated for typical hard magnets including tetragonal CoPt-type and hexagonal YCo5 alloys. The exchange stiffness is strongly anisotropic in all studied alloys. This anisotropy makes the domain wall surface tension anisotropic. Competition between this anisotropic surface tension and magnetostatic energy controls the formation and dynamics of nanoscale domain structures in hard magnets. Anisotropic domain wall bending is described in detail from the general point of view and with application to cellular Sm-Co magnets. It is shown that the repulsive cell-boundary pinning mechanism in these magnets is feasible only due to the anisotropic exchange stiffness if suitably oriented initial pinning centers are available. In polytwinned CoPt-type magnets the exchange stiffness anisotropy controls the orientation of macrodomain wall segments. These segments may reorient both statically during microstructural coarsening and dynamically during the macrodomain wall splitting in external field. Reorientation of segments may facilitate their pinning at antiphase boundaries.

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“…If pinning is generated by planar faults like APB's, the maximum unpinning threshold H u is achieved when DW segments (DWS) are parallel to the faults. If the planar fault is represented micromagnetically as a slab of thickness w ≪ δ with modified exchange and anisotropy constants A ′ and K ′ , then H u is given by 17 :…”

Section: Atomistic Scale: Pinning At Antiphase Boundariesmentioning

confidence: 99%

“…with α = π/3 3/2 ≃ 0.60 (our definition of δ contains an extra factor π compared to the notation of Ref. 17). Positive or negative H u corresponds to DW attraction to or repulsion from the fault.…”

Section: Atomistic Scale: Pinning At Antiphase Boundariesmentioning

confidence: 99%

Atomistic, microstructural and micromagnetic aspects of the multiscale modeling of hysteretic phenomena in hard magnets

Belashchenko

Antropov

2002

Journal of Magnetism and Magnetic Materials

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We formulated a technique which combines the first-principles, micromagnetic and microstructural calculations and allows us to study the nature of hysteretic phenomena in hard magnets. Two distinct sources of coercivity in polytwinned CoPt type magnets, domain wall pinning at antiphase boundaries and splitting at twin boundaries, are illustrated for a realistic microstructure. Methodology of multiscale modelling of hysteretic phenomena in nanoscale magnets is discussed.

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Sound propagation anomalies and phase diagram of chromium alloys

Cited by 4 publications

References 4 publications

Effect of transverse magnetic correlations on a coupled order parameter: Shifted transition temperatures and thermal hysteresis

Effect of transverse magnetic correlations on a coupled order parameter: Shifted transition temperatures and thermal hysteresis

Anisotropy of exchange stiffness and its effect on the properties of magnets

Atomistic, microstructural and micromagnetic aspects of the multiscale modeling of hysteretic phenomena in hard magnets

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