Synthesis and physical properties of a new layered ferromagnet Cr_1.21Te₂

Single crystals of a new layered compound, Cr1.21Te2, were synthesized via a vapor transport method. The crystal structure and physical properties were characterized by single crystal and powder x-ray diffraction, temperature- and field-dependent magnetization, zero-field heat capacity, and angle-resolved photoemission spectroscopy. Cr1.21Te2, containing two Cr sites, crystalizes in a trigonal structure with a space group P-3 (No. 147). The Cr site in the interstitial layer is partially occupied. Physical property characterizations indicate that Cr1.21Te2 is metallic with hole pockets at the Fermi energy and undergoes a ferromagnetic phase transition at similar to 173K. The magnetic moments align along the c axis in the ferromagnetic state. Based on low-temperature magnetization, the spin stiffness constant, D, and spin excitation gap, Delta, were estimated according to Bloch's law to be D = 94 +/- 17 meV angstrom(2) and Delta = 0.45 +/- 0.33 meV, suggesting its possible application as a low dimensional ferromagnet.