Measurement of high frequency conductivity of oxide-doped anti-ferromagnetic thin film with a near-field scanning microwave microscope

Abstract

In this manuscript, we describe how the map of high frequency conductivity distribution of an oxide-doped anti-ferromagnetic 200 nm thin film can be obtained from the quality factor (Q) measured by a near-field scanning microwave microscope (NSMM). Finite element analysis (FEA) is employed to simulate the NSMM tip-sample interaction and obtain a curve related between the simulated quality factor (Q) and conductivity. The curve is calibrated by a standard Cu thin film with thickness of 200 nm, together with NSMM measured Q of Ag, Au, Fe, Cr and Ti thin films. The experimental conductivity obtained by the NSMM for IrMn thin films with various doped concentrations of Al2O3 is found consistent with conventional voltammetry measurement in the same tendency. That conductivity decreases as the content of doped Al2O3 increases. The results and images obtained demonstrate that NSMM can be employed in thin film analysis for characterization of local electrical properties of materials in a non-destructive manner and for obtaining a map of conductivity distribution on the same film.

Developments of Interfacial Measurement Using Cavity Scanning Microwave Microscopy

“…Circuit analog estimation was used to assess the electrical properties for the resonator. The interaction between the sample and tip was modeled using FEA so that the resonant frequency and Q values corresponding to the sample were retrievable [ 34 ]. The simulation was verified using a specimen of thin Cu membrane to quantify the simulated Q variation with the conductivity plot.…”

Imaging of soft material with carbon nanotube tip using near-field scanning microwave microscopy

“…Fig. 1(a) shows a near-field scanning microwave microscope (NSMM) system of our own design [18,19]. It consists of a high quality factor (Q) λ/4 coaxial resonator [3], a scanning platform attached to x-y direction motors, a piezoelectric motor, a vector network analyzer (VNA) (Agilent Technologies N5230A), and some lenses mounted to a charge-coupled device (CCD).…”

An approach to determine solution properties in micro pipes by near-field microwave microscopy

“…As novel measuring equipment, near-field microwave microscopy (NSMM) can test electromagnetic properties of various forms of materials-mainly categorized into solid and liquid materials. On the one hand, NSMM has been proved feasible on many solid samples since most of them have little loss with few disturbances, for example, few-layer graphene flakes with monolayers [1], elemental and compounded metal thin films [2], carrier mobility for gallium arsenide [3], nanostructure in silicon [4] and so on. Some new NSMM applications such as imperfection detection on graphene films [5], opaque anti-counterfeiting markers [6] or determining substance properties in nanoscale [7][8][9] are also very promising.…”