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Magnetismo inducido químicamente y magnetorresistencia en La{0.8}Sr{1.2}Mn{0.6}Rh{0.4}O{4)
P D Battle1, A M Bell, S J Blundell
1Inorganic Chemistry Laboratory, Chemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
Journal of the American Chemical Society
|August 2, 2001
Resumen
Las interacciones magnéticas de corto alcance en La{0.8}Sr{1.2}Mn{0.6}Rh{0.4}O{4) conducen a una magnetorresistencia negativa por debajo de 200 K. Un campo magnético aplicado induce un ordenamiento ferromagnético, que persiste hasta 50 K.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- El magnetismo es el magnetismo.
Sus antecedentes:
- Investigando las interacciones magnéticas en óxidos complejos como las fases similares a K(2) NiF(4).
- Comprender el papel de los cationes de manganeso (Mn) y rodio (Rh) en las propiedades magnéticas.
Objetivo del estudio:
- Para caracterizar el comportamiento magnético de La{0.8) Sr{1.2) Mn{0.6) Rh{0.4) O{4).
- Para explorar la influencia de los campos magnéticos externos en el ordenamiento magnético.
- Para dilucidar los mecanismos detrás de la magnetorresistencia negativa y el comportamiento del vidrio giratorio.
Principales métodos:
- Magnetometría y espectroscopia de espín de muones (μSR) para sondear las interacciones magnéticas.
- Difracción de neutrones para determinar el orden del momento atómico bajo campos magnéticos.
- Mediciones de la resistividad eléctrica para evaluar la magnetorresistencia.
Principales resultados:
- Se observaron interacciones magnéticas significativas de corto alcance por debajo de 200 K.
- Magnetorresistencia negativa (ρ/ρ0 ≈ 0.5 a 14 T, 108 K) por debajo de 200 K.
- El ordenamiento ferromagnético inducido por el campo (≈3.38(7) μB/Mn) a 2 K, persiste hasta 50 K en 5 T.
- Comportamiento del vidrio de espín observado por debajo de 20 K sin un campo aplicado.
Conclusiones:
- Los campos magnéticos externos pueden inducir un orden ferromagnético de largo alcance en este material.
- Rh3+ influye en las interacciones de intercambio magnético, controlando las transiciones de fase magnética.
- Los cambios en la estructura de la banda electrónica bajo campos aplicados contribuyen al ordenamiento magnético inducido.
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