Magnetic Structures and Properties of Mn(1-t)Co(t)As.

Selte, Kari; Kjekshus, Arne; Valde, Gunnar; Andresen, Arne F.; Sandström, M.

doi:10.3891/acta.chem.scand.30a-0468

Cited by 16 publications

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“…The complicated magnetic phase diagram is probably related to the change of the lattice parameters with pressure. As shown in figure 1(b), while both a and c-axises change only slightly, the b-axis lattice parameter was found to decrease dramatically with pressure [8,19]. However, the crystal symmetry remains the same without a structural phase transition.…”

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confidence: 85%

First-principles calculations of the magnetic and electronic structures of MnP under pressure

Liu

Zheng

et al. 2017

J. Phys.: Condens. Matter

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Manganese monophosphide (MnP) shows complicated magnetic states varying with both temperature and pressure. We calculate the magnetic and electronic structures of MnP at different pressures using first-principles methods and obtain spiral ground states whose propagation vector changes from the c-axis at low pressure to the b-axis at high pressure. In between, we find a ferromagnetic state, as observed in the experimental phase diagram. The propagation vector of the spiral states is found to vary nonmonotonically with pressure, consistent with neutron measurements. Our results indicate that the complicated magnetic phase diagram originates from a delicate competition between neighboring exchange interactions between the Mn-ions. At all pressures, the electronic structures indicate the existence of quasi-one-dimensional charge carriers, which appear in the ferromagnetic state and become gapped in the spiral state, and anisotropic three-dimensional charge carriers. We argue that this two-fluid behavior originates from the special crystal structure of MnP and may be relevant for understanding the pairing mechanism of the superconductivity at the border of the high pressure spiral phase.

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confidence: 85%

First-principles calculations of the magnetic and electronic structures of MnP under pressure

Liu

Zheng

et al. 2017

J. Phys.: Condens. Matter

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Section: Introductionmentioning

confidence: 99%

First-principles calculations of the magnetic and electronic structures of MnP under pressure

Xu,

Liu,

Zheng

et al. 2017

Preprint

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Manganese monophosphide (MnP) shows complicated magnetic states varying with both temperature and pressure. We calculate the magnetic and electronic structures of MnP at different pressures using first-principles methods and obtain spiral ground states whose propagation vector changes from the c-axis at low pressure to the b-axis at high pressure. In between, we find a ferromagnetic state, as observed in the experimental phase diagram. The propagation vector of the spiral states is found to vary nonmonotonically with pressure, consistent with neutron measurements. Our results indicate that the complicated magnetic phase diagram originates from a delicate competition between neighboring exchange interactions between the Mn-ions. At all pressures, the electronic structures indicate the existence of quasi-one-dimensional charge carriers, which appear in the ferromagnetic state and become gapped in the spiral state, and anisotropic three-dimensional charge carriers. We argue that this twofluid behavior originates from the special crystal structure of MnP and may be relevant for understanding the pairing mechanism of the superconductivity at the border of the high pressure spiral phase.

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“…[16,17,21] As examples of such materials we have the compounds Gd 5 (Ge x Si 1-x ) 4 , [10,16,21] the hydrides of La(Fe 1-x Si x ) 13 , [14,16,17] MnFeP x As 1-x , [13,16,17] and MnAs and its derivatives as MnAs 1-x Sb x , [11,12,22,23] Mn 1-x T x As, T ¼ Ti, V, Cr, Fe, Co, Ni [24][25][26][27][28] and Cu. [20] Usually people considers FOPT keeping close analogy with first order transitions presented by simple elements or compounds, [21,[29][30][31][32] which, in the framework of the Gibbs phase rule, are materials described by two degrees of freedom (DOF).…”

Section: Introductionmentioning

confidence: 99%

A General Approach to First Order Phase Transitions and the Anomalous Behavior of Coexisting Phases in the Magnetic Case

Gama

Campos

Coelho

et al. 2009

Adv Funct Materials

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First order phase transitions for materials with exotic properties are usually believed to happen at fixed values of the intensive parameters (such as pressure, temperature, etc.) characterizing their properties. It is also considered that the extensive properties of the phases (such as entropy, volume, etc.) have discontinuities at the transition point, but that for each phase the intensive parameters remain constant during the transition. These features are a hallmark for systems described by two thermodynamic degrees of freedom. In this work it is shown that first order phase transitions must be understood in the broader framework of thermodynamic systems described by three or more degrees of freedom. This means that the transitions occur along intervals of the intensive parameters, that the properties of the phases coexisting during the transition may show peculiar behaviors characteristic of each system, and that a generalized Clausius–Clapeyron equation must be obeyed. These features for the magnetic case are confirmed, and it is shown that experimental calorimetric data agree well with the magnetic Clausius–Clapeyron equation for MnAs. An estimate for the point in the temperature‐field plane where the first order magnetic transition turns to a second order one is obtained (the critical parameters) for MnAs and Gd5Ge2Si2 compounds. Anomalous behavior of the volumes of the coexisting phases during the magnetic first order transition is measured, and it is shown that the anomalies for the individual phases are hidden in the behavior of the global properties as the volume.

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Magnetic Structures and Properties of Mn(1-t)Co(t)As.

Cited by 16 publications

References 0 publications

First-principles calculations of the magnetic and electronic structures of MnP under pressure

First-principles calculations of the magnetic and electronic structures of MnP under pressure

First-principles calculations of the magnetic and electronic structures of MnP under pressure

A General Approach to First Order Phase Transitions and the Anomalous Behavior of Coexisting Phases in the Magnetic Case

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