Determination of Magnetocaloric Effect in La0.67Ba0.33MnO3 from Direct and Indirect Measurements

Öz

In this study, we investigated magnetocaloric properties of the perovskite compound La0.67Ba0.33MnO3 synthesized by sol-gel technique. The temperature dependent magnetization measurements at 50Oe applied magnetic field showed that the sample displays a ferromagnetic-paramagnetic transition with increasing temperature. ΔTad of the sample was measured both on increasing and decreasing fields directly. The results indicate that the magnetocaloric effect is largely reversible due to showing the same ΔTad for both cases.

Anahtar Kelimeler

• Magnetic refrigeration,Magnetocaloric effect,Adiabatic temperature change,Manganite

La0.67Ba0.33MnO3’ deki Manyetokalorik Etkinin Doğrudan ve Dolaylı Ölçümlerden Belirlenmesi

Öz

Bu çalışmada, sol-jel yöntemi ile üretilen La0.67Ba0.33MnO3 perovskit bileşiğindeki manyetokalorik etki özelliği incelenmiştir. 50 Oe uygulanan manyetik alan altında sıcaklığa bağlı manyetizasyon ölçümlerinden örneğin sıcaklığın artışıyla birlikte ferromanyetik-paramanyetik faz geçişi gösterdiği gözlenmiştir. Örneğin ΔTad değeri alan artarken ve azalırken doğrudan ölçülmüştür. Sonuçlar ΔTad’nin her iki durumda da aynı değeri göstermesinden manyetokalorik etkinin tersinir olduğunu göstermektedir.

Anahtar Kelimeler

• Manyetik soğutma,Manyetokalorik etki,Adiyabatik sıcaklık değişimi,Manganit

Kaynakça

1. 1. Guo, Z. B, Du, Y. W., Zhu, J. S., Huang, H., Ding, W. P., Feng, D., 1997. Large Magnetic Entropy Change in Perovskite-Type Manganese Oxides. Phy. Rev. Lett. 78: 1142.
2. 2. Sarkar, P., Mandal, P., Choudhury, P., 2008. Large Magnetocaloric Effect in Sm0.52Sr0.48MnO3 in Low Magnetic Field. Appl. Phys. Lett. 92, 182506.
3. 3. Kumar, V. S., Mahendiran R., 2011. Effect of Impurity Doping at the Mn-site on Magnetocaloric Effect in Pr0.6Ca0.4Mn0.96 B0.04O3 (B=Al, Fe, Cr, Ni, Co, and Ru). J. Appl. Phys. 109, 023903.
4. 4. Das, S., Dey, T. K., 2006. Magnetocaloric Effect in Potassium Doped Lanthanum Manganite Perovskites Prepared by a Pyrophoric Method. J. Phys.: Condens. Matter 18, 7629-7641.
5. 5. Çetin, S. K., Acet, M., Güneş, M., Ekicibil, A., Farle, M., 2015. Magnetocaloric Effect in (La1-xSmx)0.67Pb0.33MnO3 (0 ≤ x ≤ 0.3). J. Alloys Comp. 650, 285-294.
6. 6. Phan, M. H., Yu, S. C., 2007. Review of the Magnetocaloric Effect in Manganite Materials. J. Magn. Magn. Mater. 308, 325-340.
7. 7. Wang, Z., Xu, Q., Ni, G., Zhang, H., 2011. Magnetic Entropy Change in Perovskite Manganites La0.6Pr0.1Pb0.3MnO3 with Double Metal-insulator Peaks. Physica B 406, 4333-4337.
8. 8. Kolat, V. S., Izgi, T., Kaya, A. O., Bayri, N., Gencer, H., Atalay, S., 2010. Metamagnetic Transition and Magnetocaloric Effect in Charge-ordered Pr0.68Ca0.32-xSrxMnO3 (x=0, 0.1, 0.18, 0.26 and 0.32) Compounds. J. Magn. Magn. Mater. 322, 427-433.

9. 9. Phan, M.H., Tian, S.B., Hoang, D. Q., Yu, S. C., Nguyen, C., Ulyanov, A. N., 2003. Large Magnetic-entropy Change Above 300K in CMR Materials. J. Magn. Magn. Mater. 25-259: 309-311.
10. 10. Pecharsky, V. K., Gschneidner, K. A. Jr., 1999. Magnetocaloric Effect and Magnetic Refrigeration. J. Magn. Magn. Mater. 200: 44-56.
11. 11. Banerjee, B. K., 1964. On a Generalised Approach to First and Second Order Magnetic Transitions. Phys. Lett. 12, 16-17.
12. 12.Tishin, A. M., 1999. Handbook of Magnetic Materials, Ed. By Bushow, K. H. J. (Elsevier, Amsterdam), Vol. 12, p. 395.
13. 13. Çetin, S. K., Acet, M., Ekicibil, A., Sarıkürkçü, C., Kıymaç, K., 20 3. Reversibility in the Adiabatic Temperature Change of Pr0.73Pb0.27MnO3. J. Alloys Comp. 565, 139-143.