We conceive a model of nanosystems where Co is uniformly,randomly distributed into a CoFe2O4(CFO)matrix,and study the influences of composition and CFO antiferromagnetic exchange coupling(JCFo)on zero-field-cooled/field-cooled magnetization behavior and the dependencies of exchange bias field(HE)and coercivity(Hc)on Co/CFO interfacial coupling(JCo/CFo).composition and cooling field(HFC),based on a modified Monte Carlo method.With decreasing temperature,the zero-field-cooled and field-cooled mag-netization curves are overlapped and increasing initially,and then splitting at a critical temperature(TP),below which the field-cooled magnetization continues increasing while the zero-field-cooled magnetiza-tion exhibits a peak and drops,indicating a magnetically frozen state.A larger JCFO induces an elevated Tp and a reduced magnetization,while the opposite results are obtained by a higher Co occupation fraction(PCo).On the other hand,HE is nonmonotonic with JCo/CFO and the peak decreases and shifts to a lower JCo/CFO value for a larger PCo.Hc increases monotonically with increasing JCo/CFo Moreover,HE is inversely proportional to PCo when PCo varies from 0.11 to 0.30,indicating the exchange bias is still an interfacial effect.Finally,for a nonzero JCFO,HE may be suppressed and accompanied by the recovery of Hc with increasing HFC.Otherwise,HC for zero JCFO becomes high and insensitive to HFC.It is ascribed to the uni-form contact between Co and CFO,leading to the Co magnetization reversal and the CFO magnetization precisely controlled by HFC.This work opens a new avenue to control the exchange bias in nanosystems through interfacial randomization.

Song Yang;Yong Hu

Department of Physics,College of Sciences,Northeastern University,Shenyang 110819,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China

材料科学技术（英文版）

[1]Song Yang;Yong Hu-.Inverse dependence of exchange bias and coercivity on cooling field caused by interfacial randomization in nanosystems with Co sparsely distributed in CoFe2O4 matrix)[J].材料科学技术（英文版）,2022(03):258-267

JCFo,JCo,CFo,netization,magnetiza,JCFO,PCo

Inverse,dependence,exchange,bias,coercivity,cooling,field,caused,by,interfacial,randomization,nanosystems,sparsely,distributed,CoFe2O4,matrix,We,conceive,model,where,uniformly,randomly,into,study,influences,composition,antiferromagnetic,coupling,cooled,magnetization,behavior,dependencies,HE,Hc,HFC,modified,Monte,Carlo,method,With,decreasing,temperature,curves,are,overlapped,increasing,initially,then,splitting,critical,TP,below,which,continues,while,exhibits,peak,drops,indicating,magnetically,frozen,state,larger,induces,elevated,Tp,reduced,opposite,results,obtained,higher,occupation,fraction,On,other,hand,nonmonotonic,decreases,shifts,lower,value,increases,monotonically,Moreover,inversely,proportional,when,varies,from,still,effect,Finally,nonzero,may,suppressed,accompanied,recovery,Otherwise,HC,becomes,insensitive,It,ascribed,contact,between,leading,reversal,precisely,controlled,This,work,opens,new,avenue,through

0.44299