Effect of Ni substitution on the fragile magnetic system La5Co2Ge3
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2024-05-28
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La5Co2Ge3 is an itinerant ferromagnet with a Curie temperature, TC, of ∼ 3.8 K and a remarkably small saturated moment of 0.1 μB/Co. Here we present the growth and characterization of single crystals of the La5(Co1−xNix)2Ge3 series for 0.00 ≤x≤ 0.186. We measured powder X-ray diffraction, composition as well as anisotropic temperature dependent resistivity, temperature and field dependent magnetization along with heat capacity on these single crystals. We also measured muon-spin rotation/relaxation (μSR) for some Ni substitutions (x = 0.027, 0.036, 0.074) to study the evolution of internal field with Ni substitution. Using the measured data we infer a low temperature, transition temperature-composition phase diagram for La5(Co1−xNix)2Ge3. We find that TC is suppressed for low dopings, x≤0.014; whereas for 0.036≤x≤0.186, the samples are antiferromagnetic with a Neel temperature, TN, that goes through a weak and shallow maximum (TN∼ 3.4 K for x∼ 0.07) and then gradually decreases to 2.4 K by x = 0.186. For intermediate Ni substitutions, 0.016≤x≤0.027, two transition temperatures are inferred with TN>TC. Whereas the T−x phase diagram for La5(Co1−xNix)2Ge3 and the T−p phase diagram determined for the parent La5Co2Ge3 under hydrostatic pressure are grossly similar, changing from a low doping or low pressure ferromagnetic (FM) ground state to a high doped or pressure antiferromagnetic (AFM) state, perturbation by Ni substitution enabled us to identify an intermediate doping regime where both FM and AFM transitions occur.
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This preprint from Das, Atreyee, Tyler J. Slade, Rustem Khasanov, Sergey L. Bud'ko, and Paul C. Canfield. "Effect of Ni substitution on the fragile magnetic system La5Co2Ge3." Physical Review B 110, no. 7 (2024): 075141. doi: https://doi.org/10.48550/arXiv.2405.18495.
Published as Das, Atreyee, Tyler J. Slade, Rustem Khasanov, Sergey L. Bud'ko, and Paul C. Canfield. "Effect of Ni substitution on the fragile magnetic system La 5 Co 2 Ge 3." Physical Review B 110, no. 7 (2024): 075141. doi: https://doi.org/10.1103/PhysRevB.110.075141.
Published as Das, Atreyee, Tyler J. Slade, Rustem Khasanov, Sergey L. Bud'ko, and Paul C. Canfield. "Effect of Ni substitution on the fragile magnetic system La 5 Co 2 Ge 3." Physical Review B 110, no. 7 (2024): 075141. doi: https://doi.org/10.1103/PhysRevB.110.075141.
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This preprint is licensed as CC BY.