Competing magnetic interactions and magnetoresistance anomalies in cubic intermetallic compounds, Gd4RhAl and Tb4RhAl , and enhanced magnetocaloric effect for the Tb case

Magnetic and Transport Anomalies and Large Magnetocaloric Effect in Cubic R4PtAl (R = Ho and Er)

“…This finding, therefore, reinforces [9] that the anisotropy of the (crystal-field-split) 4f orbital (that is, aspherical nature) plays a key role for such an enhancement. (ii) The peak values of these two Pt compounds are far higher than those of the respective member of the isomorphous Rh family as well [9][10][11]. In fact, a comparison of the peak values of ∆S between Pt and Rh families suggests that this is in general true for a given R, e.g., for Gd 4 PtAl and Gd 4 RhAl, the values are ~6 and ~2.3J/kg K, respectively [6,9].…”

“…The magnetic refrigeration capacity, defined as the product of the full-width at half maximum and the peak value, is quite large-about 420 J/kg K-and comparable to many best magnetocaloric materials in this temperature range of interest [20]. This finding, therefore, reinforces [9] that the anisotropy of the (crystal-field-split) 4f orbital (that is, aspherical nature) plays a key role for such an enhancement. (ii) The peak values of these two Pt compounds are far higher than those of the respective member of the isomorphous Rh family as well [9][10][11].…”

“…There are magnetic-field-induced features as well, attributable to first-order transitions in most of these compounds. The experimental results presented in this article on Ho and Er compounds reveal fascinating magnetic and transport anomalies with an exceptional MCE, as inferred from the values of the isothermal entropy change (ΔS), in comparison with the values reported earlier for this family; this finding at Recent investigations on some members of this class of compounds have established that there are novel transport anomalies, not only in the magnetically ordered state, but also in the paramagnetic state [6][7][8][9][10][11]. Here, we focus on the heavy R members of the Pt-based family, R 4 PtAl, where the 4f states are far away from the Fermi level (thereby avoiding the complex, well-known phenomena due to 4f -hybridization in light rare-earths); Pt 5d electrons are expected to be weakly correlated, although possessing strong spin-orbit coupling.…”

“…Complexities of crystallography for this family have been discussed by Engelbert and Janka in the literature [5] and also presented in our earlier publication [7]. Recent investigations on some members of this class of compounds have established that there are novel transport anomalies, not only in the magnetically ordered state, but also in the paramagnetic state [6][7][8][9][10][11]. Here, we focus on the heavy R members of the Ptbased family, R4PtAl, where the 4f states are far away from the Fermi level (thereby avoiding the complex, well-known phenomena due to 4f-hybridization in light rare-earths); Pt 5d electrons are expected to be weakly correlated, although possessing strong spin-orbit coupling.…”

“…The compounds of the type R 4 TX (T = transition metals and X = p-block metal) with the cubic Gd 4 RhIn-type structure [2][3][4][5] provide a new platform in the field of "frustrated magnetism", as multiple sites for R seem to favor a spin-glass state, competing with antiferromagnetism (AF) and ferromagnetism (F) [6][7][8][9][10][11]. The crystal structure is shown in Figure 1 to bring out the surrounding of the three R ions.…”