Tunnelling Magnetoresistance at Low Magnetic Fields in LSMO/STO/LSMO Magnetic Tunnel Junction

Year 2017, Volume: 7 Issue: 2, 125 - 130, 30.06.2017

Ramazan Topkaya

Abstract

La
0.7Sr0.3MnO3/SrTiO3/La0.7Sr0.3MnO3 magnetic tunnel junction was grown on (001)-oriented SrTiO
3 substrate by using pulsed laser deposition technique. La0.7Sr0.3MnO3 (LSMO) was used as ferromagnetic
(FM) electrodes and SrTiO3 (STO) was used as a tunnel barrier. The effect of temperature and magnetic feld on
electrical transport properties has been investigated. Bottom electrode and junction resistances were observed to
strongly depend on temperature. Large magnetoresistance of almost 300 % was observed at 77.3 K at low magnetic
felds of a few tens of Oe. The large magnetoresistance was explained by the nearly half-metallic band structure of
La
0.7Sr0.3MnO3. The asymmetry of TMR curves was attributed to the ferromagnetic electrodes with different thickness and the differences in the electronic states of the upper and lower STO/LSMO interfaces

Keywords

La0.7Sr0.3MnO3, magnetic tunnel junction, spintronics, tunnelling magnetoresistance

LSMO/STO/LSMO Manyetik Tünel Ekleminin Zayıf Manyetik Alanlarda Tünelleme Manyetodirenci

Abstract

Darbeli lazer biriktirme tekniği kullanılarak La0.7Sr0.3MnO3/SrTiO3/La0.7Sr0.3MnO3 manyetik tünel eklemi
SrTiO
3alttaş üzerinde büyütüldü. Ferromanyetik elektrot için La0.7Sr0.3MnO3 (LSMO) ve tünelleme bariyeri için SrTiO
3 (STO) kullanıldı. Sıcaklığın ve manyetik alanın elektriksel özelliklere etkisi araştırıldı. Alt elektrot ve eklem
dirençlerinin çok güçlü bir şekilde sıcaklığa bağlı olduğu gözlemlendi. 77.3 K sıcaklık ve zayıf manyetik alanlarda
yaklaşık % 300’lük yüksek manyetodirenç gözlemlendi. Gözlemlenen yüksek manyetodirenç La0.7Sr0.3MnO3’ün
yarımetalik band yapısından kaynaklanır. TMR eğrilerinin asimetrik yapısı, farklı kalınlıktaki elektrotlar ile üst ve
alt STO/LSMO ara yüzeylerin elektronik yapılarının farklılığına atfedildi

Keywords

La 0.7Sr0.3MnO3, manyetik tünel eklemi, spintronik, tünelleme manyetodirenci

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