1 Tunable Low-Field Magnetoresistance Properties in (La 0.7 Ca 0.3 MnO 3 ) 1- x :(CeO 2 ) x Vertically Aligned Nanocomposite Thin Films Xingyao Gao, 1 Leigang Li, 1 Jie Jian, 1 Jijie Huang, 1 Xing Sun, 1 Di Zhang, 1 and Haiyan Wang 1,2* 1 School of Materials Engineering, Purdue University, West Lafayette, IN 47907, United States 2 School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States *To whom correspondence should be addressed: hwang00@purdue.edu