Nature of the ferromagnetic-antiferromagnetic transition in Y${}_{1-x}$La${}_x$TiO${}_3$

Abstract

We explore the magnetically-ordered ground state of the isovalently-substituted Mott-insulator Y${}_{1-x}$La${}_x$TiO${}_3$ for $x$ $\le$ 0.3 via single crystal growth, magnetometry, neutron diffraction, x-ray magnetic circular dichroism (XMCD), muon spin rotation ($\mu$SR) and small-angle neutron scattering (SANS). We find that the decrease in the magnetic transition temperature on approaching the ferromagnetic (FM) - antiferromagnetic (AFM) phase boundary at the La concentration $x_c$ $\approx$ 0.3 is accompanied by a strong suppression of both bulk and local ordered magnetic moments, along with a volume-wise separation into magnetically-ordered and paramagnetic regions. The thermal phase transition does not show conventional second-order behavior, since neither a clear signature of dynamic critical behavior nor a power-law divergence of the magnetic correlation length is found for the studied substitution range; this finding becomes increasingly obvious with substitution. Finally, from SANS and magnetometry measurements, we discern a crossover from easy-axis to easy-plane magneto-crystalline anisotropy with increasing La substitution. These results indicate complex changes in magnetic structure upon approaching the phase boundary.

16 pages, 16 figures

References in corpus (5)

• Orbital Physics in the Perovskite Ti Oxides
• Optical response of ferromagnetic YTiO_3 studied by spectral ellipsometry
• Pressure induced ferromagnetism in antiferromagnetic Fe_1.03Te
• Two-component electronic phase separation in the doped Mott insulator Y${}_{1-x}$Ca${}_x$TiO${}_3$
• Muon spin relaxation study of LaTiO3 and YTiO3

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• Two-component electronic phase separation in the doped Mott insulator Y${}_{1-x}$Ca${}_x$TiO${}_3$
• Effect of random antiferromagnetic exchange on the spin waves in a three-dimensional Heisenberg ferromagnet
• Magnetic resonance study of rare-earth titanates