n-型铪掺杂锰氧化物薄膜和异质结的光、电、磁场调制及应力效应

发布时间：2018-04-04 09:18

  本文选题：钙钛矿锰氧化物　切入点：输运特性　出处：《苏州科技大学》2017年硕士论文

【摘要】：由于电子自旋、电荷、轨道和晶格之间的强关联,钙钛矿型过渡族金属氧化物材料呈现出极为丰富的新奇物理现象,如金属-绝缘体转变、相分离以及超大磁阻效应等。锰氧化物各量子态具有相近的自由能,导致多个亚稳态的竞争与共存,使得锰氧化物对物理场十分的敏感。本论文中,以钙钛矿锰氧化物材料La_(0.9)Hf_(0.1)MnO_3(LHMO)作为研究对象,系统地研究其薄膜与异质结在光、电、磁和应力场的调制下的电输运性质。具体内容如下:1、采用脉冲激光沉积的制备工艺,在SrTiO_3(001)衬底上制备LHMO薄膜,改变退火氧压和退火时间,研究退火条件对薄膜电输运特性的影响。结果表明提高退火氧压和延长退火时间都会提高薄膜的金属绝缘转变温度。2、研究晶格失配对LHMO薄膜电输运特性的影响。选用不同晶格常数的衬底提供不同的应力,分别在SrTiO_3(STO),LaAlO_3(LAO),(La Al O_3)_(0.3)(Sr_2AlTaO_6)_(0.7)(LSAT)、KTaO_3(KTO)、和(Zr,Y)O_2(YSZ)单晶衬底上生长LHMO薄膜。研究发现应力会降低薄膜的金属-绝缘转变温度,从而影响材料的电输运特性。3、研究应力场与光场共同作用下,LHMO薄膜电输运特性的变化。在光场的调控下,薄膜出现光致电阻效应,并将两种不同应力作用下的光致电阻率进行对比,发现压应力作用下的光致电阻效应较为明显。4、研究薄膜受磁场调控的影响时,比较电子导电的薄膜与空穴导电的薄膜的磁输运特性。在LSAT衬底上分别制备LHMO和La_(0.8)Ba_(0.2)MnO_3(LBMO)薄膜,LHMO薄膜是电子导电型,LBMO薄膜是空穴导电型。结果发现无论是电子导电的薄膜还是空穴导电的薄膜,在磁场的调制下,薄膜的电阻都会随磁场的增大而变小,并在某一温度有薄膜的最大庞磁电阻率。5、研究La_(0.9)Hf_(0.1)MnO_3/0.05 wt%Nb-SrTiO_3(NSTO)异质结的性能,包括异质结的整流效应和光电效应。对异质结进行光、电、磁场的多场调控,研究整流效应的场调控。结果表明在多场调制下,反向电流变大的同时,正向电流也变大,异质结表现出更好的整流特性。
[Abstract]:Due to the strong correlation between electron spin charge orbital and lattice perovskite-type transition metal oxide materials exhibit novel physical phenomena such as metal-insulator transition phase separation and super-large magnetoresistive effect.The quantum states of manganese oxide have similar free energy, which leads to the competition and coexistence of many metastable states, which makes manganese oxide very sensitive to physical field.In this paper, the perovskite manganese oxide material LaCo0.9HfD _ (0.1) MNO _ (3) LHMOs is taken as the research object, and the electrical transport properties of the thin film and heterojunction under the modulation of light, electricity, magnetism and stress field are systematically studied.The specific contents are as follows: 1. LHMO thin films were prepared on SrTiO-1 substrates by pulsed laser deposition. The effects of annealing conditions on the electrical transport properties of the films were studied by changing the annealing oxygen pressure and annealing time.The results show that increasing annealing oxygen pressure and prolonging annealing time can increase the transition temperature of metal insulation. The effect of lattice mismatch on the electrical transport characteristics of LHMO thin films is studied.閫夌敤涓嶅悓鏅舵牸甯告暟鐨勮‖搴曟彁渚涗笉鍚岀殑搴斿姏,鍒嗗埆鍦⊿rTiO_3(STO),LaAlO_3(LAO),(La Al O_3)_(0.3)(Sr_2AlTaO_6)_(0.7)(LSAT),KTaO_3(KTO),鍜，

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