Relevancy between Thermochromic and Magnetic Property of La_1-xSr_xMnO₃ (x=0.2 and 0.33) Smart Radiation Thin Film Materials Prepared by Magnetron Sputtering

Abstract:

La1-xSrxMnO3 thin films with x=0.2 and 0.33 were prepared by magnetron sputtering method for its potential application on thermal control of spacecraft. The materials show a phase transition from ferromagnetic metal phase with a low infrared emittance to paramagnetic insulator phase with a high emittance. Because of the thermochromic property, they can automatically change their infrared emittance greatly in response to environment temperature and thermal load and keep the spacecraft electronic components working normally. A superconduction quantum interference device magnetometer was used to study magnetization over the temperature range 100–315 K. Temperature dependence of total hemispherical emittance was carried out in a liquid nitrogen cooled vacuum chamber by a steady state calorimetric method. Thermal emittance results indicate an obvious tuneability of both La0.8Sr0.2MnO3 and La0.67Sr0.33MnO3 thin films. Compared to La0.8Sr0.2MnO3 thin film, La0.67Sr0.33MnO3 thin film has a higher transition temperature and bigger emittance tuneability. Based on phase separation concept, the thermal emittance was fitted by two-energy-level Boltzmann distribution of metal phase volume fraction fH. The measured magnetization curves were fitted in terms of mean-field approximation theory. The volume fraction of ferromagnetic phase fM was not coinciding with the fH very well. This result showed the fH and the fM plays a different role on thermal emittance property.

• Periodical: Applied Mechanics and Materials (Volumes 303-306)
• Pages: 7-11
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.303-306.7
• Online since: February 2013
• Authors: Chun Hua Wu, Min Xu, Jie Bing Wang, Lin Li, Yin Zhong Zhao, Hua Ping Zuo
• Keywords: La_1-xSr_xMnO₃, Phase Separation, Thermal Emittance, Thin Film

References

[1] A. P. Ramirez, J. Phys.: Condens. Matter 9 (1997) 8171.

[2] J. M. D. Coey, M. Viret, S. Von Molnar, Adv. Phys. 48 (1999) 167.

[3] K. Shimazaki, S. Tachikawa, A. Ohnishi, Y. Nagasaka, Int. J. Thermophys. 22 (2001) 1549.

[4] K. Fukuzawa, A. Ohnishi, Y. Nagasaka, Int. J. Thermophys. 23 (2002) 319.

[5] S. L. Yuan, Z. Y. Li, G. Peng, C. S. Xiong, Y. H. Xiong, and C. Q. Tang, Appl. Phys. Lett. 79 (2001) 90.

[6] M. Fath, S. Freisem, A. A. Menovsky, Y. Tomioka, J. Aarts, J. A. Mydosh. Science 285(1999), 1540.

DOI: 10.1126/science.285.5433.1540

[7] T. Becker, C. Streng, Y. Luo, V. Moshnyaga, B. Damaschke, N. Shannon, K. Samwer, Phys. Rev. Lett. 89 (2002) 2372031.

DOI: 10.1103/physrevlett.89.237203

[8] G. Li, H .D. Zhou, S. J. Feng, X. J. Fan, X. G. Li, J. Appl. Phys. 92 (2002) 1406.

[9] C. Kittel, Introduction to solid state physics, 6th edition. Wiley, New York, (1986).

[10] L. W. Zhang, Casey Israel, Amlan Biswas, R. L. Greene, Alex de Lozanne, Science 298 (2002) 805.