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Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus

Temperature dependent HE (a) and HC (b) with a cooling field of HFC = 5 kOe for FexAu1 − x(50 nm)/FeNi(5 nm) bilayers with x = 4%, 8%, 11% and 14%.The inset shows the ZFC-FC magnetization curves for the Fe11Au89(50 nm) film under HFC = 50 Oe with T varying between 5 K to 300 K.
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f1: Temperature dependent HE (a) and HC (b) with a cooling field of HFC = 5 kOe for FexAu1 − x(50 nm)/FeNi(5 nm) bilayers with x = 4%, 8%, 11% and 14%.The inset shows the ZFC-FC magnetization curves for the Fe11Au89(50 nm) film under HFC = 50 Oe with T varying between 5 K to 300 K.

Mentions: The quantities of HE and HC are calculated based on HE = (HC1 + HC2)/2 and HC = (−HC1 + HC2)/2, where HC1 and HC2 denote the coercive fields at the descending and the ascending branches of the M-H hysteresis loop, respectively. The temperature dependences of HE and HC in FexAu1 − x/FeNi bilayers are shown in Fig. 1, where x = 4%, 8%, 11% and 14% and HFC is 5 kOe for these measurements. In order to confirm the SG nature of the FeAu layers, ZFC-FC curves were measured with an applied field of 50 Oe. The inset in Fig. 1 shows typical features of spin glass behaviors for a FeAu single layer with x = 11%. The value of the freezing temperature (TF) for this sample is about 30 K, below which the ZFC and FC curves become bifurcated. DC memory effect25 has also been observed in this sample (not shown), providing a further proof of the SG state. Similar SG behaviors can be found in all other FuAu single layer films with x varying from 4% to 14%.


Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

Temperature dependent HE (a) and HC (b) with a cooling field of HFC = 5 kOe for FexAu1 − x(50 nm)/FeNi(5 nm) bilayers with x = 4%, 8%, 11% and 14%.The inset shows the ZFC-FC magnetization curves for the Fe11Au89(50 nm) film under HFC = 50 Oe with T varying between 5 K to 300 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562234&req=5

f1: Temperature dependent HE (a) and HC (b) with a cooling field of HFC = 5 kOe for FexAu1 − x(50 nm)/FeNi(5 nm) bilayers with x = 4%, 8%, 11% and 14%.The inset shows the ZFC-FC magnetization curves for the Fe11Au89(50 nm) film under HFC = 50 Oe with T varying between 5 K to 300 K.
Mentions: The quantities of HE and HC are calculated based on HE = (HC1 + HC2)/2 and HC = (−HC1 + HC2)/2, where HC1 and HC2 denote the coercive fields at the descending and the ascending branches of the M-H hysteresis loop, respectively. The temperature dependences of HE and HC in FexAu1 − x/FeNi bilayers are shown in Fig. 1, where x = 4%, 8%, 11% and 14% and HFC is 5 kOe for these measurements. In order to confirm the SG nature of the FeAu layers, ZFC-FC curves were measured with an applied field of 50 Oe. The inset in Fig. 1 shows typical features of spin glass behaviors for a FeAu single layer with x = 11%. The value of the freezing temperature (TF) for this sample is about 30 K, below which the ZFC and FC curves become bifurcated. DC memory effect25 has also been observed in this sample (not shown), providing a further proof of the SG state. Similar SG behaviors can be found in all other FuAu single layer films with x varying from 4% to 14%.

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus