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By means of alloying appropriate amounts of MnNiSi and MnFeGe, materials are found that undergo a paramagnetic to ferromagnetic transition close to room temperature, accompanied by a huge volume change. Thanks to this volume change, application of moderate pressures leads to a remarkable enhancement of the magnetocaloric response. Work like this may open new opportunities in the development of new solid-state magnetic refrigeration devices.

A novel physical phenomenon has been observed that resembles a large asymmetric switchinglike magnetoresistance at low applied fields in bulk metamagnetic Heusler alloys. A thermally activated isothermal forward metamagnetic transition with a signature of a pronounced time-dependent relaxation was observed in a bulk B-substituted off-stoichiometric Ni-Mn-In Heusler alloy, whereas the reverse metamagnetic transition exhibited the usual athermal behavior with no thermal activation. The asymmetry between the forward and reverse metamagnetic transitions resulted in a large switchinglike, low-field magnetoresistance (\ensuremath{\sim}16% for a field change of $B$ = 0 \ensuremath{\rightarrow} 0.25 T at $T$ = 304 K) in the bulk Heusler alloys, ${\mathrm{Ni}}_{50}{\mathrm{Mn}}_{35}{\mathrm{In}}_{15\ensuremath{-}x}{\mathrm{B}}_{x}$ (1 \ensuremath{\leqslant} $x$ \ensuremath{\leqslant} 2).

A comprehensive study of the temperature (T) and magneticfield (H) dependence of magnetic entropy change (�S M) for different materials exhibiting inverse magnetocaloric effect (IMCE) is reported. We show thatS M follows a power-law dependence of H (�S M ∼ H n ; n is an exponent) for these compounds. In contrast to conventional magnetocaloric effect (CMCE), n is independent of H and T in the case of IMCE. As a result, a universal master curve can be constructed to describeS M(T) of the IMCE systems for different H without rescaling the temperature axis. This is completely different from that reported for CMCE, where the rescaling of the temperature axis with the introduction of at least one reference temperature is needed for constructing a universal curve. The different universal behavior of IMCE is attributed to the constant value of n in any field and temperature, which is a generic feature of IMCE systems irrespective of their magnetic state and nature of phase transition. From the proposed phenomenological universal curve, one can extrapolate the magnetocaloric properties of IMCE systems in any temperature and magnetic field range, which would be helpful in designing controlled active magnetic refrigeration devices.

Resistivity, magnetoresistance, magnetization, and in-field heat capacity measurements were performed of the $\mathrm{Gd}{\mathrm{Pt}}_{2}$ intermetallic compound. The magnetocaloric parameters $\ensuremath{\Delta}{T}_{\mathit{ad}}$ and $\ensuremath{-}\ensuremath{\Delta}S$ were derived from in-field heat capacity data. Comparison has been made between the magnetocaloric effect $\ensuremath{-}\ensuremath{\Delta}S$ and difference in resistivity $\ensuremath{-}\ensuremath{\Delta}\ensuremath{\rho}\phantom{\rule{0.3em}{0ex}}[=\ensuremath{\rho}(H)\ensuremath{-}\ensuremath{\rho}(0)]$ as a function of temperature. There is distinct difference in the temperature dependence of $\ensuremath{-}\ensuremath{\Delta}S$ and $\ensuremath{-}\ensuremath{\Delta}\ensuremath{\rho}$ below the ferromagnetic transition temperature. However, after removing the domain wall contribution from $\ensuremath{-}\ensuremath{\Delta}\ensuremath{\rho}$, the natures of the $\ensuremath{-}\ensuremath{\Delta}S$ and $\ensuremath{-}\ensuremath{\Delta}\ensuremath{\rho}$ dependence as a function of temperature are similar. Our observation indicates that the domain wall contribution in the magnetocaloric effect is negligible in spite of the fact that it has a significant contribution in magnetotransport.