Electronic State of Low Spin MnAs(P)

Haneda, Sho; Kazama, Noriaki; Yamaguchi, Yasuo; Watanabe, Hiroshi

doi:10.1143/jpsj.42.1212

Cited by 28 publications

(3 citation statements)

References 9 publications

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“…28 The MnAs unit cell volume in any phase is too big to justify a high-spin to low-spin transition. In MnAs 1−x P x the change from high spin to low spin is observed, 10,29,30 for volumes around 120 Å 3 , while the unit cell of MnAs remains always larger than 130 Å 3 . Another possible explanation of the secondorder phase transition assumes a random distribution of distortions over the main B8 1 phase.…”

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confidence: 96%

Ab initiostudy of the magnetostructural properties of MnAs

Rungger

Sanvito

2006

Phys. Rev. B

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The magnetic and structural properties of MnAs are studied with ab initio methods and by mapping total energies onto a Heisenberg model. The stability of the different phases is found to depend mainly on the volume and on the amount of magnetic order, confirming previous experimental findings and phenomenological models. It is generally found that for large lattice constants the ferromagnetic state is favored, whereas for small lattice constants different antiferromagnetic states can be stabilized. In the ferromagnetic state the structure with minimal energy is always hexagonal, whereas it becomes orthorhombically distorted if there is an antiferromagnetic alignment of the magnetic moments in the hexagonal plane. For the paramagnetic state the stable cell is found to be orthorhombic up to a critical lattice constant of about 3.7 Å, above which it remains hexagonal. This leads to the second-order structural phase transition between paramagnetic states at about 400 K, where the lattice parameter increases above this critical value with rising temperature due to the thermal expansion. We also evaluate the magnetic susceptibility as a function of temperature, from which a semiquantitative description of the MnAs phase diagram emerges.

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confidence: 96%

Ab initiostudy of the magnetostructural properties of MnAs

Rungger

Sanvito

2006

Phys. Rev. B

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“…We illustrate this by data for x = 0.06. From earlier works, an antiferromagnetic double spiral H a -type ordering was proved by single-crystal neutron diffraction for MnAs 0.925 P 0.075 , 34 whereas powder neutron diffraction (PND) showed that the H a helimagnetic structure disappears at fields above 1 T. However, the emergence of new magnetic peaks is indicative of a different incommensurate structure with long periodicity. For MnAs 0.90 P 0.10 , PND shows that ferromagnetism occurs in an intermediate temperature range, with H a order below and above, whereas MnAs 0.82 P 0.18 is fully ferromagnetic below T C 31 with a moment of 1.46 μ B aligned along [010].…”

Section: ■ Magnetic Propertiesmentioning

confidence: 98%

Total Scattering Study of Local Structural Changes in MnAs_1–xP_x Influenced by Magnetic Interactions

et al. 2021

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The interplay between fluctuations of the local structure and magnetic interactions is of great importance for phenomena like superconductivity, colossal magnetoresistance, and frustrated magnetism. Such local distortions are often subtle and difficult to probe. The metallic MnAs1–x P x (x = 0.06, 0.12, 0.18) solid solution represents a sensitive model system, currently analyzed by variable-temperature X-ray total scattering (TS). A second-order transition (Pnma to P63/mmc) occurs on heating, intimately coupled to magnetic ordering at low temperatures and a temperature-induced low- to high-spin transition for manganese. Intrinsic compositional fluctuations along with a particular magneto-volumetric coupling to low- and high-spin like states triggers formation of local high-symmetry nanosized domains in an orthorhombically deformed matrix that eventually converts globally into a high-temperature hexagonal arrangement. These features are only traced by TS analyses, whereas diffraction provides a regular second-order transition with, e.g., cationic displacements defined by Rietveld analysis acting as order parameter. The coexistence model provides good fits of the TS data and, on average, translates nicely into a continuous V(T) thermal expansion relation with maximum expansivity in the range where the TS data shows the largest difference between local (<20 Å) and intermediate-range (20–80 Å) structures. The degree of local distortions, Mn(As, P)6 octahedra inclusive, is a result of volume-dependent electronic properties as well as magnetic interactions. This study demonstrates how X-ray TS can conveniently give essential insights into the local symmetry fluctuations from the perspective of strong magnetic interactions.

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“…Anion substitution with phosphorous has the same effect as applying hydrostatic pressure to MnAs. Extensive studies of the system MnAs,-,P, for 0.00 < x < 0.18 have been carried out, partly focusing on the coupling of the spin conversion (1s cf hs) with the continuous structural MnP ++ NiAs-type transition, and partly considering the complicated helical magnetic structures found at low temperatures [12][13][14][15][16][17][18][19][20][21]. Furthermore, Zieba et al [22] reported that the spin and structural transition can be induced if a magnetic field is applied to MnAso,,P, o4 samples in its MnP-type helimagnetic mode (latent ferromagnetism).…”

Section: Introductionmentioning

confidence: 99%

A Mössbauer study of⁵⁷Fe in MnAs

et al. 1988

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A 57Fe Mossbauer spectroscopy study of Mn,-,Fe,As with x = 0.01, 0.03 and 0.15 has been undertaken. For x = 0.01 a peculiar temperature dependence of the hyperfine field has been observed in the ferromagnetic phase. The change in the electric field gradient at the first order transition at 275(5) K has been explained on the basis of a change in the electron configuration of the 3d-electrons of Fe using the crystal field splitting model developed for MnAs by Haneda and coworkers. The magnetic hyperfine field at the Fe nucleus is very small as compared to the corresponding hyperfine field at the Mn nucleus. Stable extra phases, not observed by X-ray diffraction, involving Fe atoms are formed for x = 0.01 and x = 0.03 when heating the sample above 400 K and 540 K respectively.

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Electronic State of Low Spin MnAs(P)

Cited by 28 publications

References 9 publications

Ab initiostudy of the magnetostructural properties of MnAs

Ab initiostudy of the magnetostructural properties of MnAs

Total Scattering Study of Local Structural Changes in MnAs_1–xP_x Influenced by Magnetic Interactions

A Mössbauer study of⁵⁷Fe in MnAs

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Electronic State of Low Spin MnAs(P)

Cited by 28 publications

References 9 publications

Ab initiostudy of the magnetostructural properties of MnAs

Ab initiostudy of the magnetostructural properties of MnAs

Total Scattering Study of Local Structural Changes in MnAs1–xPx Influenced by Magnetic Interactions

A Mössbauer study of57Fe in MnAs

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Product

Resources

About

Total Scattering Study of Local Structural Changes in MnAs_1–xP_x Influenced by Magnetic Interactions

A Mössbauer study of⁵⁷Fe in MnAs