خواص استاتیک و دینامیک مغناطیسی نانوذرات La0/8Sr0/2MnO3

نویسندگان

پژوهشکده الکتروسرام، دانشگاه صنعتی مالک اشتر، شاهین شهر، اصفهان

چکیده

در این تحقیق، نانوذراتLa0/8Sr0/2MnO3 با میانگین اندازه بلورک‌های 20 نانومتر به روش سل- ژل ساخته شده‌اند. نمونه‌ها توسط پراش پرتو ایکس همراه با تحلیل ریتولد، تصاویر میکروسکوپی الکترونی روبشی گسیل میدانی و طیف‌سنجی تبدیل فوریه مادون‌قرمز ارزیابی شدند. خواص مغناطیسی استاتیک نانوذرات مانند مغناطش اشباع، ممان مغناطیسی مؤثر و کسر فاز فرومغناطیسی با روش‌های مختلف و با اندازه‌گیری حلقه پسماند مغناطیسی در دمای اتاق بررسی شده است. خواص دینامیک مغناطیسی نانوذرات با اندازه‌گیری پذیرفتاری مغناطیسی متناوب برحسب دما و در بسامد‌های مختلف بررسی شده است. از مدل‌های نیل- برون، وگل- فولچر و مدل بحرانی کند شدن آرام و کمیت‌های تجربی برای تمایز رفتار ابر پارامغناطیسی و شیشه ابراسپینی در نانوذرات استفاده شده است. از ارزیابی داده‌های تجربی با مدل‌های ذکر شده، زمان واهلش، انرژی ناهمسانگردی مغناطیسی و ثابت ناهمسانگردی مغناطیسی مؤثر تعیین شده است. نتایج به‌دست آمده رفتار ابر‌پارامغناطیس برهم‌کنشی را در بین نانوذرات LSMO پیشنهاد می‌کند.
 

کلیدواژه‌ها


عنوان مقاله [English]

Static and Dynamic Magnetic Properties of La0.8Sr0.2MnO3 Nanoparticles

نویسندگان [English]

  • A. Rostamnejadi
  • M. K. Esmaeilzadeh
Electroceram Research Center, Malek Ashtar University of Technology,
چکیده [English]

In this research, nanoparticles of La0.8Sr0.2MnO3 with mean crystallite size of 20 nm have been prepared by sol gel method. The sample has been characterized by X-Ray Diffraction (XRD) using Rietveld refinement, Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared (FTIR) spectroscopy. The static magnetic properties such as saturation magnetization, effective magnetic moment and ferromagnetic phase fraction of the nanoparticles are determined by different techniques using magnetic hysteresis loop at room temperature. The magnetic dynamic properties of crystalls are studied by measuring AC magnetic susceptibility versus temperature at different frequencies. Néel-Brown, Vogel-Fulcher, critical slowing down models and empirical parameters are used to distinguish between superparamagnetic and superspin glass behaviour in the nanoaprticles. By fitting the experimental data with the models, relaxation time, critical view, magnetic anisotropy energy and effective magnetic anisotropy constant have been estimated. The obtained results support the presence of interacting superparamagnetic behaviour between magnetic nanoparticles of La0.8Sr0.2MnO3.
 

کلیدواژه‌ها [English]

  • Manganite
  • Sol-gel
  • magnetic nanoparticles
  • superparamagnetism
  • Magnetic Dynamics
  • AC Magnetic Susceptibility
  • Magnetic Anisotropic
  • Superspin glass
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