摘　要：采用磁控濺射方法制備了以Pt為緩沖層和保護(hù)層的NiFe/FeMn薄膜.在NiFe/FeMn界面插入Pt,發(fā)現(xiàn)交換偏置場(Hex)隨著插層Pt厚度(tPt)的增加而減小.一個重要的現(xiàn)象是當(dāng)Pt插層厚度為0.4nm時,在Het-tPt衰減曲線并非單純指數(shù)下降,而是出現(xiàn)一個"凸起".通過對樣品磁矩隨Pt插層厚度的變化規(guī)律進(jìn)行分析,發(fā)現(xiàn)隨Pt插層厚度的增加,樣品的磁矩先逐漸增大,然后又有所下降,并且穩(wěn)定在某一值;表明在樣品制備過程中,NiFe與FeMn之間的相互作用(如界面反應(yīng)),使得在NiFe/FeMn界面存在磁死層,Pt的插入抑制了NiFe/FeMn界面磁死層的產(chǎn)生,有利于交換耦合;另一方面,Pt的插入隔離了NiFe和FeMn的直接接觸,使得FeMn對NiFe的釘扎作用減弱,不利于交換耦合.兩個方面的共同作用,使得當(dāng)Pt插層為某一合適厚度時,Hex-tPt曲線出現(xiàn)"凸起".

關(guān)鍵詞：交換耦合;Pt插層;磁死層

分類號：O484.4+3　文獻(xiàn)標(biāo)識碼：A

文章編號：1672-7126(2008)增刊-005-04

Pt Spacer and Exchange Coupling between NiFe and FeMn Layers

Jin Chuan　 Liu Yang　 Li Minghua　 Yu Guanghua　

      基金項目：國家自然科學(xué)基金(No.50471093,50671008);北京市自然科學(xué)基金(No.2052014)和教育部"新世紀(jì)優(yōu)秀人才支持計劃"(No.NCET-04-0104)資助課題
作者簡介：于廣華,聯(lián)系人:E-mail:ghyu＠m(xù)ater.astb.edu.cn

作者單位：金川（北京科技大學(xué)材料物理與化學(xué)系,北京,100083）
　　　　　劉洋（北京科技大學(xué)材料物理與化學(xué)系,北京,100083）
　　　　　李明華（北京科技大學(xué)材料物理與化學(xué)系,北京,100083）
　　　　　于廣華（北京科技大學(xué)材料物理與化學(xué)系,北京,100083）

參考文獻(xiàn)：

[1]Meildejohn W H,Bean C P.New Magnetic Anisotropy.Phys Rev,1956,102(5):1413-1414
[2]Dieny B,Speriosu V S,Parkin S S P,et al.Giant magnetoresistive in soft ferromagnetic multilayers.Phys Rev B,1991,43 (1):1297-1300
[3]Parkin S S P,Reche K P,Semant M G,et al.Exchange-biased magnetic tunnel junctions and application to nonvolatile magnetic random access memory.J Appl Plays,1999,85(8):5828-5833
[4]Mauri D,Siegmann H C.Simple model for thin ferromagnetic films exchange coupled to an antiferromagnetic substrate.J Appl Phys,1987,62(7):3047-3049
[5]Malozemoff A P.Mechanisms of exchange anisutropy.J Appl Plays,1988,63(8):3874-3879
[6]Koon N C.Calculations of Exchange Bias in Thin Films with Ferromagnetic/Antiferromagnetic Interfaces.Phys Rev Lett,1997,78(25):4865-4868
[7]Miltényi P,ierlings M,Keller J,et al.Diluted Antiferromagnets in Exchange Bias:Proof of the Domain State Model.Plays Rev Lett,2000,84(18):4224-4227
[8]Mewes T,Stamps R L.Exchange bias of antiferromagnets with random anisotropies and perfectly compensated interfaces.Appl Phys Lett,2004,84(19):3840-3842

[9]Gokemeijer N J,Ambrose T,Often C L.Long-Range Exchange Bias across a Spacer Layor.Pys Bey Lett,1997,79(21):4270-4273
[10]Gruyters M,Gierlings M,Riegel D.Rapid suppression of exchange bias across thin Au spacer layers.Phys Bey B,2001,64(13):132401(1)-132401(4)
[11]Thomas L,Kellock A J,Parkin S S P.On the exchange biasing through a nonmagnetic spacer layer.J Appl Phys,2000,87(9):5061-5063
[12]Mewes T,Roos B F P,Demokritov S O,et al.Oscillatory exchange bias effect in FeNi/Cu/FeMn and FeNi/Cr/FeMn trilayer systems.J Appl Phys,2000,87(9):5064-5066
[13]Garcia F,Sort J,Rodmacq B,et al.Large anomalous enhancement of perpendicular exchange bias by introductions of a nonmagnetic spacer between the ferromagnetic and antiferronmgnetic layers.Appl Phays Lett,2003,83(17):3537-3539
[14]Sort J,Garcia F,Rodmacq B,et al.Enhancement of exchange bias through a non-magnetic spacer.J Magn Magn Mater,2004,272-276:355-356
[15]Sort J,Baltz V,Garcia F,et al.Tailoring perpendicular exchange bias in[Pt/Co]-lrMn multilayers.Phys Rev B,2005,71:054411(1)-054411(7)
[16]Schroeder T,Zaumseil P,Weidner G,et al.On the epitaxy of twin-free cubic (111) praseodymium sesquioxide films on Si(111).J Appl Phys,2006,99:014101(1)-014101(9)
[17]Yu G H,Chai C L,Zhu F W,et al.Interface reaction of NiO/NiFe and its influence on magnetic properties,Appl Plays Left,2001,78(12):1706-1708
[18]Kewalewski M,Butlor W H,Moghadam N,et al.The effect of Ta on the magnetic thickness of permalloy (Ni81 Fe19) films.J Appl Phys,2000,87(9):5732-5734
[19]Yu G H,Zhao H C,Li M H,et al.Interface reaction of Ta/ Ni81Fe19 or Ni81Fe19/Ta and its suppression.Appl Plays Lett,2002,80(3):455-457
[20]張睿,劉洋,金川,等.PL/(Pt/Co)n/FeMn/Pt多層膜中Pt插層對交換偏置場的影響.真空科學(xué)與技術(shù)學(xué)報,2007,27(4):302-304