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TT: Fachverband Tiefe Temperaturen
TT 26: Correlated Magnetism – Frustrated Systems
TT 26.4: Vortrag
Mittwoch, 19. März 2025, 10:15–10:30, H33
Magnetic-field induced phase transition crossover in the triangular lattice antiferromagnet Ba3CoSb2O9 — •Sanjay Kumar1, Rashi Nathawat1, Arvind Kumar Yogi2, and Satyapal S. Rathore3 — 1Functional Ceramics and Smart Materials Lab, Department of Physics, Manipal University Jaipur, Jaipur - 303007, India. — 2UGC-DAE Consortium for Scientific Research, Indore - 452001, India. — 3Department of Physics, Cluster University of Jammu, Jammu - 180001, India.
The effect of magnetic field on the ground state properties of triangular lattice antiferromagnet (TLAF) compound Ba3CoSb2O9. The temperature-dependent X-ray diffraction (10 to 300 K) shows no structural changes. The temperature and field-dependent susceptibility indicate that TLAF orders antiferromagnetically below TN ∼ 3 K. The susceptibility follows a Curie-Weiss law (above 100 K) with qCW = -133.2 K. The frustration index (f ∼ 44 ) indicates a highly frustrated system. Magnetization curves (dM/dH) at 2 K reveal field-induced spin-flop transitions near H ∼ 9 T. Magnetic susceptibility shows a broad peak at Tmax = 5 K, becoming more pronounced with increasing field. A spin-glass signature appears near Tg ∼ 6.5 K but vanishes at higher fields. Interestingly, the magnetic ground state in this compound shows a crossover from the various possible spin orders. A significant shoulder-like hump in heat capacity near Tc ∼ 15 K suggests structural changes, deviating from the typical λ-anomaly. The change in magnetic properties is attributed to the interplay between antisite defects, quantum fluctuations, and geometric frustration in TLAF.
Keywords: triple perovskite; frustrated magnetism; triangular-lattice; quantum fluctations