| Phase Separation and Microwave Response of Epitaxial and Polycrystalline Manganite Films |
| S. Asmontas a,d , A. Abrutis b , J. Gradauskas a,c A. Lucun a , A. Oginskis a , V. Plausinaitiene a,b , A. Suziedelis a,c and B. Vengalis a,c a Semiconductor Physics Institute, A. Gostauto 11, 2600 Vilnius, Lithuania b Department of General and Inorganic Chemistry, Vilnius University Naugarduko 24, 2006 Vilnius, Lithuania c Vilnius Gediminas Technical University, Sauletekio al. 11, 2040 Vilnius, Lithuania d KTU Panevezys Institute, Klaipedos 3, 5319 Panevezys, Lithuania |
| Full Text PDF |
| The resistance, magnetoresistance, and resistance response under microwave irradiation (f=10 and 35GHz) were measured for epitaxial and polycrystalline La 0.67 Ca 0.33 MnO 3 and La 0.67 Sr 0.33 MnO 3 thin films in the temperature range 78÷300K. The microwave induced resistance increase observed for the epitaxial films in a narrow temperature range below the ferromagnetic to paramagnetic transition temperature T c certifies coexistence of low resistance (ferromagnetic) and high resistance (paramagnetic) regions in the manganites. Resistance of polycrystalline films decreased under microwave irradiation in a wide temperature range below T c . The effect was explained in terms of microwave assisted hopping of carriers in high resistance regions formed at grain boundaries of the polycrystalline films. |
| DOI: 10.12693/APhysPolA.105.141 PACS numbers: 75.47.Gk, 75.47.Lx, 07.57.Kp |