The results show that the change of surface Cr_2O_3 thickness induces to the difference in tunneling barrier, which alters magnetotransport properties of CrO_2.

• 实验结果表明CrO_2颗粒表面Cr_2O_3层厚度的改变导致颗粒间隧穿势垒的变化，从而使CrO_2颗粒间的磁输运性质发生了改变。