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Structural transformation induced by magnetic field and colossal magnetoresistance response above 313 K in MnAs

J. Mira·F. Rivadulla·J. Rivas·A. Fondado·R. Caciuffo·F. Carsughi·T. Guidi·J. B. Goodenough
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Abstract

MnAs exhibits a first-order phase transition from a ferromagnetic, high-spin metal NiAs-type hexagonal phase to a paramagnetic, lower-spin insulator MnP-type orthorhombic phase at T_C = 313 K. Here, we report the results of neutron diffraction experiments showing that an external magnetic field, B, stabilizes the hexagonal metallic phase above T_C. The phase transformation is reversible and constitutes the first demonstration of a bond-breaking transition induced by a magnetic field. At 322 K the hexagonal structure is restored for B > 4 tesla. The field-induced phase transition is accompanied by an enhanced magnetoresistance of about 17 % at 310 K. We discuss the origin of this phenomenon, which appears to be similar to that of the colossal magnetoresistance response observed in some members of the manganese perovskite family.

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J. Mira, F. Rivadulla, J. Rivas, A. Fondado, R. Caciuffo, F. Carsughi, T. Guidi, J. B. Goodenough. 2002-01-25. Structural transformation induced by magnetic field and colossal magnetoresistance response above 313 K in MnAs. https://doi.org/10.1103/physrevlett.90.097203

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