Volume 118, Number 5, June 2017
|Number of page(s)||7|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||18 August 2017|
Large magnetoresistance over a wide temperature range in Eu0.99La0.01TiO3
Physics Department, Faculty of Science, National University of Singapore - 2 Science Drive 3, Singapore 117551, Republic of Singapore
Received: 22 May 2017
Accepted: 25 July 2017
We report the magnetization (M), electrical resistivity and magnetoresistance (MR) in the electron-doped antiferromagnet Eu0.99La0.01TiO3. While M(T) measured upon cooling indicates the occurrence of a paramagnetic to antiferromagnetic transition at , zero field goes through a broad maximum at . The application of an external magnetic field raises the value of Tp and decreases the magnitude of ρ at Tp leading to a negative magnetoresistance (MR) effect. A large MR of for is observed at 2.5 K with a remarkable change occurring in sub-tesla magnetic fields ( for ). In addition, significant MR prevails even up to 10 TN ( at 50 K). While MR over a wide field range for can be satisfactorily described by the equation , MR scales with M below TN. Unlike the resistivity, thermopower is insensitive to magnetic fields. Our results indicate that electrons doped into the Ti-3d conduction band are strongly coupled to localized 4f7 spins of Eu2+ ions via the exchange interaction. We suggest that the observed MR is most likely caused by the field-induced suppression of 4f spin fluctuations and the subsequent reduction of the scattering of 3d electrons. This is a unique example in perovskite oxides where the magnetoresistance of 3d electrons is controlled by spin fluctuations associated with 4f localized electrons of a rare-earth ion.
PACS: 75.47.Gk – Colossal magnetoresistance / 72.20.My – Galvanomagnetic and other magnetotransport effects / 75.50.Ee – Antiferromagnetics
© EPLA, 2017
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