Dresden 2020 – wissenschaftliches Programm
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TT 3.10: Vortrag
Montag, 16. März 2020, 12:00–12:15, HSZ 201
Magnetic Phase diagram and thermal expansion studies of NiTiO3 — •Kaustav Dey1, Sven Sauerland1, Johannes Werner1, Rabindranath Bag2, Surjeet Singh2, and Rüdiger Klingeler1 — 1Kirchhoff Institute of Physics , Heidelberg University, Germany — 2IISER Pune, Maharashtra, India
We report the magnetic phase diagram of S=1 magnetodielectric NiTiO3 single crystals grown by the optical floating zone technique. The high-quality single crystals have been studied by specific heat, by magnetometry up to 60 T, and by thermal expansion and magnetostriction measurements up to 15 T, respectively. The compound evolves long-range antiferromagnetic order at TN = 22.5 K with spins lying in the ab−plane. Pronounced anomalies in the thermal expansion coefficients (αi, (i=a,b)) at TN indicate strong magnetoelastic coupling in NiTiO3. Magnetic length and entropy changes as detected by α and cp obey Grüneisen scaling which evidences one dominant (spin) degree of freedom driving the transitions. In addition, the magnetic phase diagram features a spin-reoriented phase below Bc=1.2 T which suggests the presence of a small in-plane anisotropy. Notably, spin-reorientation is associated with a first-order-like anomaly in the magnetostriction. The high-field behavior of magnetization is linear and isotropic with saturation at 36 T thereby facilitating constructing the entire magnetic phase diagram.