創新型磁譜儀的實現與鈷鐵硼薄膜及鐵氧體的鐵磁共振量測

Instrumentation of the innovative magnetic spectrometer and the FMR study of a CoFeB thin film and Ferrites

張恩可(En-Ke Chang)

指導教授 ： 蔡崇智

長榮大學/資訊暨工程學院/資訊管理學系(所)/碩士(2015年)

https://doi.org/10.6833/CJCU.2015.00011

摘要

利用鐵磁共振(FMR；ferromagnetic resonance)的量測方法作為研究物質的磁特性是很有效且被廣為使用的一個量測技術。本研究的主題從儀器的硬體設置，程式的撰寫，量測的控制到數據的擷取，我們開發了一套創新型的鐵磁共振磁譜儀(FMR spectrometer)來作為對物質的磁特性包括磁矩動態的研究。本磁譜儀主要的特點之一是採用一個蜿蜒線(meanderline)來同時作為傳輸器(transmitter)與接收器(receiver)的功能。此蜿蜒線的結構設計可產生一個與外加DC磁場垂直的射頻(rf)磁場(頻率一般在微波範圍)來做為FMR的驅動場並同時作為訊號的探測器。其中對共振訊號的擷取我們並採用了鎖相偵測技術(lock-in detection technique)。本磁譜儀的設計可做多次量測藉以求得訊號的平均值，因而可以大大提高訊號的信噪比(SNR；signal-to-noise ratio)值。本磁譜儀主要的特點之一是不受限於樣品的大小，因此非常適合使用於對磁性薄膜的量測。本磁譜儀的量測功能包含例如可進行不同頻率的量測(寬頻)、改變磁場與樣品之間不同角度的量測、固定頻率改變微波功率的量測、改變樣品面角度的量測以及利用parallel pumping量測法以得到受測樣品所謂的butterfly curve。利用這個磁譜儀，我們分別對幾個不同材料的樣品進行FMR的實驗，其中包括對Permalloy 薄膜(Ni80Fe20, 1m厚度)、單層CoFeB (80 nm)/MgO薄膜、以及多個(RE, Me)3Fe5O12多晶樣品(此系列為受委託量測之樣品)進行磁性的探討。對這些樣品在不同的量測參數下所得到的結果以及數據的分析將在本論文中加以討論。

關鍵字

鐵磁共振 ； 蜿蜒線 ； 鎖相偵測技術

並列摘要

Ferromagnetic Resonance (FMR) is a widely used and highly effective technology, used for the study of the magnetic characteristics of materials. The topic of this study ranges from programming, measurement control and data acquisition, and for this, we have developed an innovative FMR spectrometer for studying the magnetic moment dynamic of magnetic material. The main feature of this FMR spectrometer is to employ a meander line, which is not only a transmitter but also a receiver. The meander line structure will produce a radio-frequency (rf) magnetic field (which will approximately radiate microwave frequencies) that is perpendicular to the extra DC magnetic field, (which is the rf field as the FMR driving field and signal probe). In these magnetic fields, to acquire resonance signals we employ a lock-in detection technique and use it to measure the average repeatedly to improve the signal-to-noise ratio (SNR). This FMR spectrometer is not limited to sample size, so it is therefore very suitable for measurements of magnetic thin films. The function of this can be measured in different frequencies (e.x. broad-band), and can alter the degree between an extra DC magnetic field and a sample. It can also alter microwave power at a fixed frequency, alter the degrees of a sample surface, and utilize parallel pumping measurement methods for the butterfly curve. By utilizing this spectrometer, we carry out FMR measurements and explore several different material samples, which include but aren’t limited to- film Permalloy (Ni80Fe20, 1m thickness), single CoFeB (80 nm)/MgO, and many polycrystalline (RE, Me)3Fe5O12 samples respectively. The results and analysis of the data of these samples under different measurement parameters obtained will be discussed in this paper.

並列關鍵字

Ferromagnetic Resonance ； Meander line ； Lock-in detection technique

參考文獻

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