Ferromagnetic Cr₄PtGa₁₇: A Half-Heusler-Type Compound with a Breathing Pyrochlore Lattice

Abstract

We describe the crystal structure and elementary magnetic properties of a previously unreported ternary intermetallic compound, Cr4PtGa17, which crystallizes in a rhombohedral unit cell in the noncentrosymmetric space group R3m. The crystal structure is closely related to those of XYZ half-Heusler compounds, where X, Y and Z were reported to be single elements only, most straightforwardly illustrated by writing the formula as (PtGa2)(Cr4Ga14)Ga (X=PtGa2, Y = Cr4Ga14, Z = Ga). The magnetic Cr occupies a breathing pyrochlore lattice. Ferromagnetic ordering is found below TC ~61 K, by both neutron diffraction and magnetometer studies, with a small, saturated moment of ~0.25 B/Cr observed at 2 K, making Cr4PtGa17 the first ferromagnetically ordered material with a breathing pyrochlore lattice. A magnetoresistance of ~140% was observed at 2 K. DFT calculations suggest that the material has a nearly-half-metallic electronic structure. The new material, Cr4PtGa17, the first realization in possessing both half-Heusler-type structure and breathing pyrochlore lattice, might pave a new way to achieve novel types of half-Heusler compounds with breathing pyrochlore lattice.

Interplay between Charge-Density-Wave, Superconductivity, and Ferromagnetism in CuIr2–xCrxTe4 Chalcogenides

“…The value of saturated moment is much less than effective moment. This phenomenon has also been observed in other Cr-based materials such as Cr4PtGa17, 57 CrBe12, 58 and CuCr2Te4. 42 The magnetization is not saturated at 7…”

High spin-polarization in a disordered novel quaternary Heusler alloy FeMnVGa

“…The low value of the RRR points toward the presence of structural disorder which earlier has been confirmed by Mössbauer, Neutron and EXAFS measurements [47][48][49][50]. We attempted to fit the resistivity data in the magnetically ordered state (5 < T < 270 K) using the following formula [51,52],…”

Beyond single tetrahedron physics of the breathing pyrochlore compound Ba3Yb2Zn5O11

“…Thus it is of great interest to synthesize and understand breathing pyrochlore materials. The majority of the work performed on the breathing pyrochlore-based compounds has focused on Cr-based spinels with S = 3/2 [28][29][30][31][32][33][34][35][36], while the studies performed on quantum systems with S = 1/2 remain limited to Ba 3 Yb 2 Zn 5 O 11 in powder form [37][38][39][40][41][42].…”