Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

[PDF] http://dx.doi.org/10.3952/lithjphys.46113

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 46, 85–88 (2006)

THERMAL RESPONSE OF GRAINED La_0.67Ca_0.33MnO₃ FILMS TO MICROWAVE RADIATION
K. Repšas, A. Laurinavičius, R.-A. Vaškevičius, F. Anisimovas, A. Deksnys, and B. Vengalis
Semiconductor Physics Institute, A. Goštauto 11, LT-01108 Vilnius, Lithuania
E-mail: anis@pfi.lt

Received 14 November 2005

Response to a microwave radiation was studied for grained La_0.67Ca_0.33MnO₃ films (d = 0.15 and 1.30 μm) grown by pulsed laser deposition on MgO (100) substrates. Thermal nature of the response has been certified for the films at T = 78 K. A mechanism of the response has been proposed that takes into account different role of grains and intergrain boundaries on dc and high frequency currents flowing in the films. Assuming a nonzero intergrain boundary capacitance, we point out that the microwave radiation heats mainly the low resistance grains rather than the intergrain boundaries. Meanwhile, dc current flowing in the films is determined by temperature-dependent resistance of the intergrain media.

Keywords: manganite thin films, microwave radiation
PACS: 75.47.Lx, 75.47De, 78.70.Gq

ŠILUMINIS GRANULIUOTŲ La_0,67Ca_0,33MnO₃ SLUOKSNIŲ ATSAKAS Į MIKROBANGĘ SPINDULIUOTĘ
.K. Repšas, A. Laurinavičius, R.-A. Vaškevičius, F. Anisimovas, A. Deksnys, B. Vengalis
Puslaidininkių fizikos institutas, Vilnius, Lietuva

Aptiktas tiriamųjų sluoksnių atsakas mikrobangei spinduliuotei ir nustatyta, kad jis yra šiluminės prigimties. Pateiktas atsako mechanizmo paaiškinimas, rodantis, jog elektrinei talpai šuntuojant tarpgranulinių jungčių omines varžas, mikrobangė spinduliuotė labiausiai kaitina granules, kurios, šildydamos tarpgranulines jungtis, pakeičia jų ominę varžą, o kartu ir sluoksnyje tekančios nuolatinės srovės stiprį.

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