Intergrain magnetoresistance and resistance relaxation of La0.7Sr0.3MnO3 thin films in pulsed magnetic fields up to 60 T

✍ Scribed by Nadejda Kozlova; Theresia Walter; Kathrin Dörr; Dieter Eckert; Axel Handstein; Yu. Skourski; Karl-Hartmut Müller; Ludwig Schultz

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 224 KB
• Volume: 346-347
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2004.01.023

✦ Synopsis

The magnetoresistance of textured and non-textured polycrystalline thin films of La 0.7 Sr 0.3 MnO 3 has been measured in pulsed magnetic fields up to 60 T between 4.2 and 300 K. The non-textured film shows a linear increase with increasing field of the magnetoconductance at low temperatures which is attributed to a constant high-field susceptibility at grain boundaries (GB). The time dependence of resistance has been recorded starting B10 ms after the field pulses. For both polycrystalline films, logarithmic relaxation and an unexpected increase of the relaxation rate with decreasing temperature down to 1.9 K is observed. This type of relaxation is absent in an epitaxial film of La 0.7 Sr 0.3 MnO 3 and smaller for the textured one of the polycrystalline films, indicating its origin in a structurally disturbed layer between misaligned grains. It might be caused by a spin glass-like state at some of the GB within the conduction path.