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update MRM, CurieTM
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jeanwsr committed Jan 4, 2020
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Binary file modified 居里温度测量/TeX/CurieTM.pdf
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7 changes: 6 additions & 1 deletion 居里温度测量/TeX/CurieTM.tex
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\usepackage{geometry}
\geometry{left=2.5cm,right=2.5cm,bottom=2.5cm,top=2.5cm}

\usepackage[version=4]{mhchem}
\usepackage{siunitx}

\providecommand{\keywords}[1]{\textbf{关键词: #1}}

\title{近代物理实验报告10.6:居里温度测量}
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\includegraphics[width=\textwidth]{fig/fig3.pdf}
\caption{理想的$\text{ABO}_3$钙钛矿结构}\label{fig3}
\end{figure}
这些钙钛矿锰氧化物的母本氧化物是LaMnO3,Mn离子为正二价,这是一种显示反铁磁性的绝缘体,呈理想的钙钛矿结构。早在20世纪50-60年代,人们已经发现,如果用二价碱土金属离子(Sr、Ca、Pb等)部分取代三价稀土离子,Mn离子将处于混合价状态,于是,通过和离子之间的双交换作用,在一定温度($T_p$)以下、将同时出现绝缘体—金属转变和顺磁性—铁磁性转变。随着含Sr量的增加,锰氧化物的R—T曲线形状发生明显变化。
这些钙钛矿锰氧化物的母本氧化物是LaMnO3,Mn离子为正二价,这是一种显示反铁磁性的绝缘体,呈理想的钙钛矿结构。早在20世纪50-60年代,人们已经发现,如果用二价碱土金属离子(Sr、Ca、Pb等)部分取代三价稀土离子,Mn离子将处于混合价状态,于是,通过和离子之间的双交换作用\cite{jonker1950ferromagnetic}\cite{van1950electrical},在一定温度($T_p$)以下、将同时出现绝缘体—金属转变和顺磁性—铁磁性转变\cite{anderson1955considerations}\cite{zener1951interaction}。随着含Sr量的增加,锰氧化物的R—T曲线形状发生明显变化。1970-1990年间,人们陆续观察到一些不同成分的钙钛矿锰氧化物块体和薄膜,具有较大的负磁电阻效应。1994年Jin等人在$ \ce{La_{2/3}Ca_{2/3}MnO_3} $薄膜中于$ \SI{6}{T} $的磁场下观测到磁电阻MR高达99.9\%\cite{jin1994colossal}\cite{jin1994thousandfold}\cite{mccormack1994very}。这类材料具有的磁电阻被命名为庞磁电阻(CMR)。

这类材料在一定成分范围内,呈铁磁性,居里温度较高,吸引了人们极大的研究兴趣。

\section{实验仪器}
信号源、锁定放大器、数字电压表、石英管、热电偶。
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75 changes: 75 additions & 0 deletions 居里温度测量/TeX/ref.bib
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Expand Up @@ -4,4 +4,79 @@ @book{jiaocai
publisher = {南京大学出版社},
year = {2008},
edition = {2}
}

@article{jonker1950ferromagnetic,
title={Ferromagnetic compounds of manganese with perovskite structure},
author={Jonker, GH and Van Santen, JH},
journal={physica},
volume={16},
number={3},
pages={337--349},
year={1950},
publisher={Elsevier}
}

@article{van1950electrical,
title={Electrical conductivity of ferromagnetic compounds of manganese with perovskite structure},
author={Van Santen, JH and Jonker, GH},
journal={Physica},
volume={16},
pages={599--600},
year={1950}
}

@article{zener1951interaction,
title={Interaction between the d-shells in the transition metals. II. Ferromagnetic compounds of manganese with perovskite structure},
author={Zener, Clarence},
journal={Physical Review},
volume={82},
number={3},
pages={403},
year={1951},
publisher={APS}
}

@article{anderson1955considerations,
title={Considerations on double exchange},
author={Anderson, Patric W and Hasegawa, H},
journal={Physical Review},
volume={100},
number={2},
pages={675},
year={1955},
publisher={APS}
}

@article{jin1994thousandfold,
title={Thousandfold change in resistivity in magnetoresistive La-Ca-Mn-O films},
author={Jin, S and Tiefel, Th H and McCormack, M and Fastnacht, RA and Ramesh, R\_ and Chen, LH},
journal={Science},
volume={264},
number={5157},
pages={413--415},
year={1994},
publisher={American Association for the Advancement of Science}
}

@article{jin1994colossal,
title={Colossal magnetoresistance in La-Ca-Mn-O ferromagnetic thin films},
author={Jin, S and McCormack, M and Tiefel, TH and Ramesh, R},
journal={Journal of Applied Physics},
volume={76},
number={10},
pages={6929--6933},
year={1994},
publisher={AIP}
}

@article{mccormack1994very,
title={Very large magnetoresistance in perovskite-like La-Ca-Mn-O thin films},
author={McCormack, M and Jin, S and Tiefel, TH and Fleming, RM and Phillips, Julia M and Ramesh, R},
journal={Applied physics letters},
volume={64},
number={22},
pages={3045--3047},
year={1994},
publisher={AIP}
}
Binary file modified 磁电阻测量/TeX/MRM.pdf
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15 changes: 9 additions & 6 deletions 磁电阻测量/TeX/MRM.tex
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%\newcommand*{\rom}[1]{\expandafter\@slowromancap\romannumeral #1@}
\newcommand{\rom}[1]{\textup{\uppercase\expandafter{\romannumeral#1}}}
\newcommand{\parallelsum}{\mathbin{\!/\mkern-5mu/\!}}
\title{\Huge 近代物理实验报告\\\huge 10.1:各向异性磁电阻、巨磁电阻测量}
\title{近代物理实验报告10.1:各向异性磁电阻、巨磁电阻测量}
\author{xy\quad 学号\quad 匡亚明学院}
\date{2019年2月29日}
\begin{document}
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\end{enumerate}

\section{思考题}
\subsection{测量AMR后计算出来的$\rho_{av}$$\rho_0$是否相同,如不同说明什么问题?}
\subsection{按前述步骤手动测量的磁电阻曲线与自动测量的磁电阻曲线有何异同,为什么?}
\subsection{手动测量与自动测量时如何更好的选择流过样品的电流的大小?}
\subsection{测量中如何减小热效应对测量的影响?}
\subsection{样品夹具采用的材料有何要求?}
\subsection*{测量AMR后计算出来的$\rho_{av}$$\rho_0$是否相同,如不同说明什么问题?}
\subsection*{按前述步骤手动测量的磁电阻曲线与自动测量的磁电阻曲线有何异同,为什么?}
\subsection*{手动测量与自动测量时如何更好的选择流过样品的电流的大小?}
\subsection*{测量中如何减小热效应对测量的影响?}
\subsection*{样品夹具采用的材料有何要求?}

\subsection*{为什么小电阻不容易测量?为什么四探针法是比较好的方法?}


\nocite{jiaocai}
\bibliography{ref}
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