Exchange bias was observed in the Ni50Mn36Sn14 Heusler alloy after field cooling by means of hysteresis loop measurement. The hysteresis loops shift along the axis of an applied field and its magnitude significantly increased with decreasing temperature below 70K. This effect could be understood as a result of exchange anisotropy created at the interface between an antiferromagnet and a ferromagnet in the phase separated of martensitic state. Above 70K, however, the exchange bias field disappeared and the coercivity significantly reduced owing to the fact that the pinning between an antiferromagnet and a ferromagnet becomes weaker with increasing temperature.

We report the magnetic and magnetocaloric properties of Dy1−xHoxMnO3 (0 ≤ x ≤ 1). Large entropy change of 12.5 J/kg K and refrigeration capacity of 312 J/kg at 7 T for HoMnO3 is calculated based on isothermal magnetization measurements. The peak temperature of magnetic entropy change for all samples keeps the same 10.5 K, indicating that Ho3+ doping only affects the value of magnetic entropy. An unambiguous intrinsic structural transition near 7 K is first observed by strain measurement, which is believed as the origin of magnetic symmetry transition of Dy1−xHoxMnO3 and induces the magnetocaloric effect with the cooperation interaction between Dy3+/Ho3+and Mn3+ spins.

We present 75 As nuclear magnetic resonance spin-lattice and spin-spin relaxation rate data in Ba(Fe1−xCox)2As2 and Ba(Fe1−xCux)2As2 as a function of temperature, doping and magnetic field. The relaxation curves exhibit a broad distribution of relaxation rates, consistent with inhomogeneous glassy behavior up to 100 K. The doping and temperature response of the width of the dynamical heterogeneity is similar to that of the nematic susceptibility measured by elastoresistance measurements. We argue that quenched random fields which couple to the nematic order give rise to a nematic glass that is reflected in the spin dynamics.

For certain compositions Ni-Mn-Sn and related magnetic shape memory alloys undergo a martensitic transition at temperatures in the range 300 to 400 K, with the emergence of novel magnetic properties below the transition. While Ni 50 Mn 50 is an antiferromagnet, substitution of Sn on some fraction of the Mn sites in Ni 50 Mn 50-x Sn x leads to competing ferromagnetic (F) and antiferromagnetic (AF) phases at low temperatures. Details of this magnetic phase coexistence are, however, significantly lacking, particularly with respect to the AF phase. The present investigations use zero applied magnetic field 55 Mn NMR as a local probe of the magnetic properties of the alloy Ni 50 Mn 50-x Sn x with x = 10. Rich multi-peak spectra are observed, and the various components are definitively assigned to nanoscale F or AF regions. Measurements of the static nuclear hyperfine field distributions as a function of temperature, and in small applied fields, together with nuclear relaxation rates, provide detailed information on the size distributions, relative concentrations, and physical natures of these F and AF regions. The results show that the nanoscale magnetic features of the x = 10 system are substantially more complex than previous studies have suggested. We argue that the general approach used in these experiments is applicable to other such complex metal alloys, and could yield many additional insights.