Anomalies in the Young modulus at structural phase transitions in rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu)

Journal Article · Mon Aug 15 04:00:00 EDT 2011 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776111070041· OSTI ID:22028040

Snegirev, V V; Andreenko, A S ^[1]; Kozeeva, L P ^[2]

---

1. Moscow State University (Russian Federation)
2. Russian Academy of Sciences, Nikolaev Institute of Inorganic Chemistry, Siberian Branch (Russian Federation)

The elastic properties of rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu) have been experimentally studied in the temperature range of 80-300 K. The strong softening of the Young modulus {Delta}E(T)/E{sub 0} Almost-Equal-To -(0.1-0.2) of cobaltites with Lu and Yb ions has been revealed, which is due to the instability of the crystal structure upon cooling and is accompanied by an inverse jump at the second-order structural phase transition. The softening of the Young modulus and the jump at the phase transition decrease by an order of magnitude and the transition temperature T{sub s} and hysteresis {Delta}T{sub s} increase from a compound with Lu to that with Tm. A large softening of the Young modulus at the structural transition in Lu- and Yb cobaltites indicates that the corresponding elastic constant goes to zero, whereas this constant in Tm cobaltite is not a 'soft' mode of the phase transition. It has been found that the structural phase transition in Lu- and Yb cobaltites is accompanied by a large absorption maximum at the phase transition point and an additional maximum in the low-temperature phase and absorption anomalies in Tm cobaltite is an order of magnitude smaller.

• OSTI ID: 22028040
• Journal Information: Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 2 Vol. 113; ISSN JTPHES; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
BARIUM COMPOUNDS
COBALT OXIDES
COOLING
CRYSTAL STRUCTURE
ELASTICITY
HYSTERESIS
LUTETIUM COMPOUNDS
PHASE STABILITY
PHASE STUDIES
PHASE TRANSFORMATIONS
TEMPERATURE DEPENDENCE
THULIUM COMPOUNDS
TRANSITION TEMPERATURE
YOUNG MODULUS
YTTRIUM COMPOUNDS