Impact of Jahn-Teller active Mn^{3+} on strain effects and phase transitions in Sr_{0.65}Pr_{0.35}MnO_{3}

Tan, Teck-Yee and Kennedy, Brendan J. and Zhou, Qingdi and Ling, Christopher D. and Miiller, Wojciech and Howard, Christopher J. and Carpenter, Michael A. and Knight, Kevin S. (2012) Impact of Jahn-Teller active Mn^{3+} on strain effects and phase transitions in Sr_{0.65}Pr_{0.35}MnO_{3}. Physical Review B, 85 (10). p. 104107. DOI 10.1103/PhysRevB.85.104107

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Abstract

The mixed-valence manganite Sr0.65Pr0.35MnO3 has been prepared and its crystal and magnetic structure investigated between 7 and 1200 K using high-resolution powder neutron diffraction. The structural and lattice parameter data have been used to determine the octahedral tilting and spontaneous strains associated with the structural, electronic, and magnetic phase transitions. At room temperature, the structure is tetragonal and is characterized by cooperative out-of-phase tilts of the MnO6 octahedra about the c axis and a large Jahn–Teller-type distortion due to the presence of Mn3+. The sample exhibits a reversible phase transition from the cubic Pm3̅ m perovskite to a tetragonal I4/mcm structure at 750 K. The Pm3̅ m ↔ I4/mcm phase transition is continuous, and the tetragonal strain, which is dominated by the Jahn–Teller-type distortion of the MnO6 octahedra, exhibits an unusual et0.5 ∝ (Tc − T) temperature dependence. At low temperatures, a C-type antiferromagnetic structure develops with a Neel temperature TN of 250 K. The Mn magnetic moment at 7 K is 2.99(2) μB/Mn. The magnetic ordering introduces additional tetragonal strain, and this strain shows the expected quadratic dependence on the magnetic moment at low temperatures. An increase in the octahedral tilt angle at TN demonstrates an effective coupling between the magnetic ordering process and octahedral tilting.

Item Type: Article
Uncontrolled Keywords: 2012AREP; IA63;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physical Review B
Volume: 85
Page Range: p. 104107
Identification Number: 10.1103/PhysRevB.85.104107
Depositing User: Sarah Humbert
Date Deposited: 18 Apr 2012 14:27
Last Modified: 23 Jul 2013 10:04
URI: http://eprints.esc.cam.ac.uk/id/eprint/2464

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