Spin-lattice coupling, Jahn-Teller effect and the influence of the measurement rate in La{sub 0.7}Ca{sub 0.3−x}Sr{sub x}MnO{sub 3} manganites

Journal Article · Sun May 15 04:00:00 EDT 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4944656· OSTI ID:22611768

Burrola-Gándara, L. A.; Elizalde Galindo, J. T. ^[1]; Sáenz-Hernández, R. J.; Santillán-Rodríguez, C. R.; Lardizabal-Gutiérrez, D.; Pizá-Ruiz, P.; Matutes-Aquino, J. A. ^[2]

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1. Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Av. Del Charro 450 norte, 32310 Ciudad Juárez, Chihuahua, México (Mexico)
2. Centro de Investigación en Materiales Avanzados, S. C., Miguel de Cervantes 120, 31109 Chihuahua, Chihuahua, México (Mexico)

This work presents a study of how the magnetic and temperature variables, as well as the measurement rate, affect magnetic and structural phase transitions for La{sub 0.7}Ca{sub 0.3−x}Sr{sub x}MnO{sub 3} (x=0.15, 0.08, 0.07 and 0.06) manganites. A single phase rhombohedral crystal structure for Sr{sub 0.15} compound and a single phase orthorhombic crystal structure for Sr{sub 0.08}, Sr{sub 0.07}, and Sr{sub 0.06} compounds were identified by X ray diffraction. The Curie temperature adjustment to room temperature was reached for Sr{sub 0.07} sample, in which a Jahn-Teller transition was observed. This Jahn-Teller transition showed a susceptible response to 0.5, 1, 2, 3, 5 and 7 K/min measurement rates, and was revealed without measurement sequence at 234, 257, 196, 233, 245 and 238 K respectively in thermomagnetic curves (10 mT). Also, Curie temperature increases sequentially around 2 K for the same measurement rates. To avoid magnetic field effect, a differential scanning calorimetry for Sr{sub 0.07} sample was obtained in the same temperature region, for 2, 3, 5, 7 K/min showing the Jahn-Teller phase transition at 225 K and a vibrational like behavior in the heat flux below 225 K, for all the temperature rates. The latter, is related to the static to dynamic Jahn-Teller transition. Furthermore, Curie temperature appears around 284 K.

• OSTI ID: 22611768
• Journal Information: AIP Advances, Journal Name: AIP Advances Journal Issue: 5 Vol. 6; ISSN AAIDBI; ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CALCIUM COMPOUNDS
CALORIMETRY
COUPLING
CRYSTAL STRUCTURE
CRYSTALS
CURIE POINT
HEAT FLUX
JAHN-TELLER EFFECT
LANTHANUM COMPOUNDS
MAGNETIC FIELDS
MANGANATES
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
SPIN
SPIN-LATTICE RELAXATION
STRONTIUM COMPOUNDS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TRIGONAL LATTICES
X-RAY DIFFRACTION