Preparation And Electronic Transport Properties Of Perovskite Oxide SrMo_1-xMn_xO₃ Thin Films

With strongly correlated electrons and structure,perovskite transition metal oxide films exhibit interconnected internal mechanisms and rich and tunable electromagnetic properties.As one of them,SrMoO₃ films show extremely low resistivity between oxides,owing to the 4d² electronic structure of Mo ions and the tiny electron-phonon interactions inside.Mn element doping can induce magnetoelectric coupling in highly conductive SrMoO₃ thin films,inducing more diverse electromagnetic transport behaviors and expanding their applications in multi-state microelectronic devices.Therefore,in this paper,we explore the optimal pulsed laser deposing parameters of Sr Mo_1-xMn_xO₃（0≤x≤0.2）films and characterize the structure,morphology and electrical transport properties of the thin film and their influencing factors.The following results are obtained:（1）Exploring the preparation process parameters of SrMoO₃ thin film,it is found that the best substrate temperature,deposition pressure,laser energy,laser frequency and substrate is 625 ^oC,5×10^-5 Pa,2 J/cm²,2 Hz and Sr Ti O₃（001）,respectively.At this time,the film has the best epitaxial quality,with a single crystal orientation,a good degree of crystallization and a smooth surface.Changing the process conditions will affect the deposition,diffusion,and growth process of the film.The electrical transport measurement results show that the carrier type of the SrMoO₃ film is hole.The carrier concentration of the film is on the order of 10²² cm^-3,and the mobility is between 1-5cm²V^-1s^-1.As the temperature changing,the SrMoO₃ thin film exhibits paramagnetic metallic conduction behavior.Under the influence of strongly correlated spin-orbit coupling effect and electron localization,its magnetoresistance in the low-temperature and low magnetic field exhibits obvious weak localization and anti-weak localization behavior and presents anisotropy.（2）Mn doping will not change the original crystal structure of the SrMoO₃,but will cause lattice defects,which will degrade the quality of the Sr Mo_1-xMn_xO₃ films.The Mn element with 5%doping content has been able to introduce semiconductor transport transitions in the Pauli paramagnetic SrMoO₃ thin film.Higher substrate temperature is beneficial to this change and will make the thin films exhibit tiny resistance at low temperature and large linear positive magnetoresistance.For the Sr Mo_0.95Mn_0.05O₃ thin film epitaxied in a substrate temperature of 800 ^oC,the main carriers have changed from holes of the pure phase to electrons.The carrier concentration of this sample is on the order of 10²² cm^-3,and it exhibits high mobility(on the order of 10⁴ cm²V^-1s^-1)at low temperature.The cyclotron acceleration motion of its internal high-mobility electrons drifts around the magnetic domains,inducing a giant linear magnetoresistance effect,which can reach up to 10000%at 1.8 K and 14T.These phenomena may be due to the formation of two-dimensional electron gas at the interface between the Sr Mo_0.95Mn_0.05O₃ film and the Sr Ti O₃ substrate under high temperature and high vacuum preparation condition.