حذف ساختار Mn3Ga با تقارن بلوری کم از محلول آلیاژسازی Mn-Ga با افزودن Ge

نویسندگان

1 1- دانشکده فیزیک، دانشگاه یزد

2 2- دانشکده فیزیک و مرکز تحقیقات نانوافزارها و نانوساختارهای انطباقی، دانشگاه ترینیتی دوبلین، ایرلند

چکیده

در این پژوهش آسیاب‌کاری به‌عنوانی روشی برای ساخت آلیاژهایی دوتایی Mn-Ga و تأثیر آسیاب‌کاری بر فرایند تشکیل فاز نمونه‌های Mn:Ga با نسبت 2:1 و 3:1 در زمان­های 1، 2 و 5 ساعت مورد مطالعه قرار گرفت. در نمونه­های Mn:Ga با توجه به نتایج حاصل شده، ترکیب­ Mn1.86Ga با ساختار تتراگونال و گروه فضایی I4/mmm فاز پایدار بود و هم‌چنین مقادیری از ترکیب Mn3Ga با ساختار اورتورومبیک و گروه فضایی Cmca در محصول شناسایی شد. اثر افزودن Ge نیز با هدف جانشین کردن اتم Ge با اتم Ga‌، با مطالعه در نمونه Mn:Ga:Ge با نسبت
5/0: 5/0: 3 مطالعه شد. با این که بهبود ویژگی‌های مغناطیسی با افزودن Ge قابل انتظار است، اما برای نمونه مورد بررسی افزایش وادارندگی رخ داد و مغناطش اشباع نمونه تغییر محسوسی نداشت. افزایش Ge سبب از بین رفتن شانس تولید فاز نامتقارن اورتورومبیک Mn3Ga شد و در مقابل دو ساختار جدید Mn11Ge8 و MnGaGe در نمونه ایجاد شد. این تحول فازی با مطالعه رفتار مغناطیسی نمونه­ها تأیید شد. این رفتار می­تواند از نیروهای نامتوازن الکترواستاتیک مرتبط با برهم‌کنش تبادلی منگنز در ترکیب ساختار اورتورومیبک Mn3Ga و جایگزین شدن برخی اتم­های Ge با Ga ناشی ­شده باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Elimination of Mn3Ga with Low Crystal Symmetry in Alloying Mn-Ga by Ge Addition

نویسندگان [English]

  • F. Nazari 1
  • M. Hakimi 1
  • H. Mokhtari 1
  • A.S. Esmaeily 2
1 1- Department of Physics, Yazd University, Yazd, Iran
2 2- School of Physics and CRANN, Trinity College, Dublin 2, Ireland
چکیده [English]

In this paper, milling was investigated as a method for production of Mn-Ga binary alloys and the effect of milling process on phase formation of Mn:Ga samples with 2:1 and 3:1 ratio within 1, 2 and 5 hour milling times was studied. For Mn:Ga samples, according to the results, Mn1.86Ga compound with tetragonal structure and I4/mmm space group was a stable phase. Also, some amounts of  Mn3Ga compound with orthorhombic structure and Cmca space group was observed in the Mn:Ga solution. The effect of Ge addition, with the purpose of  replacing Ge with Ga was also studied in Mn:Ga:Ge (3:0.5:0.5) sample. Although improved magnetic properties is expected with the addition of Ge, but increasing the coercivity was occurred, and saturation magnetization did not change significantly in the studied sample. Ge addition caused elimination of the possibility of formation of asymmetric orthorhombic Mn3Ga phase. In return, two new structures of Mn11Ge8 and MnGaGe were appeared. This phase change was confirmed by studying magnetic behaviour of samples. This behavior can be caused by unbalanced electrostatic forces resulting from Mn-Mn exchange interaction in Mn3Ga orthorhombic structure and substitution of some Ge atoms with Ga.

کلیدواژه‌ها [English]

  • Milling
  • crystal structure
  • magnetic properties
  • Mn
  • GA
  • Ge
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