Experiments were statistically carried out on the behavior of the vertical-Bloch-line(VBL)chains of the first kind of dumbbell domains(IDs)in garnet bubble films subjected to an in-plane field,Hip.It was found that fo...Experiments were statistically carried out on the behavior of the vertical-Bloch-line(VBL)chains of the first kind of dumbbell domains(IDs)in garnet bubble films subjected to an in-plane field,Hip.It was found that for IDs the critical in-plane field,(Hip)ID,above which their VBL chains disappear,is the same as that of ordinary hard bubbles(OHBs),H'ip.However,for IDS,the critical range of Hip for VBL chain softening is larger than that of OHBs.Besides,we also found some details of the softening process,e.g.,the collapse field range of the remaining IDs shrinks rapidly towards H_(0,mas),and this very narrow range can maintain until all IDs are softened.展开更多
An experimental and theoretical study was carried out on the break-down of vertical-Bloch-line(VBL)chains in ordinary hard bubble walls subjected to an in-plane field,H_(ip).Other than a single critical value,a critic...An experimental and theoretical study was carried out on the break-down of vertical-Bloch-line(VBL)chains in ordinary hard bubble walls subjected to an in-plane field,H_(ip).Other than a single critical value,a critical range of in-plane field,from H_(ip)^(1) to H_(ip)^(2),was found.When H_(ip)<H_(ip)^(1) the VBL chains keep unchanged;whereas when H_(ip)^(1)<H_(ip)<H_(ip)^(2),more and more hard domains are softened.Above H_(ip)^(2) all VBL chains are broken-down.A theoretical analysis showed that the critical range of H_(ip) is originated from the serpentine curving of domain walls,and a relation H_(ip)^(2)/H_(ip)^(1)=√2,was obtained,which is in good agreement with the experiments.展开更多
The“softening”process of the first kind of dumbbell domains(IDs)with the increase of temperature was experimentally revealed as follows:IDs first convert to ordinary hard bubbles(OHBs)through a partial loss of the v...The“softening”process of the first kind of dumbbell domains(IDs)with the increase of temperature was experimentally revealed as follows:IDs first convert to ordinary hard bubbles(OHBs)through a partial loss of the vertical Bloch lines(VBLs)in their walls and then these OHBs convert to soft(normal)bubbles(SBs)through a further loss of VBLs.As a result,the critical temperature for the break down of VBL chains of IDs is apparently higher than OHBs.展开更多
The aexercisegexperiment shows that the dumbbell domains,which can eventually contract to circular form and then collapse,should be classified as a kind of dumbbells rather than hard bubbles.Thus dumbbell domains can ...The aexercisegexperiment shows that the dumbbell domains,which can eventually contract to circular form and then collapse,should be classified as a kind of dumbbells rather than hard bubbles.Thus dumbbell domains can be divided into two kinds:ID and HD.Their static characteristics are reported,and typical photos are presented.展开更多
The bias field dependence of the rotation direction of the dumbbells,contracted from multi-branched domains,was experimentally studied.Moreover,it was found that the rotation direction of these dumbbells can be revers...The bias field dependence of the rotation direction of the dumbbells,contracted from multi-branched domains,was experimentally studied.Moreover,it was found that the rotation direction of these dumbbells can be reversed by increasing the amplitude of the testing bias pulses with quite narrow width.展开更多
The self-collapse phenomenon of dumbbell domains was studied experimentally.The coincidence of the bias field region of self-collapse with that of collapse for both the first and second kinds of dumbbells manifests th...The self-collapse phenomenon of dumbbell domains was studied experimentally.The coincidence of the bias field region of self-collapse with that of collapse for both the first and second kinds of dumbbells manifests that two necessary conditions for self-collapse are:(1)sufficiently high number of vertical Bloch lines(VBLs)in their walls and(2)these VBLs are in high compression,and there exists the similarity between self-collapse and collapse in mechanism.展开更多
The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from t...The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.展开更多
Magnetic domain structure of hard magnetic Nd60Al10Fe20Co10 bulk metallic glass (BMG) has been studied by using magnetic force microscopy. In the magnetic force images it is shown that the exchange interaction type ma...Magnetic domain structure of hard magnetic Nd60Al10Fe20Co10 bulk metallic glass (BMG) has been studied by using magnetic force microscopy. In the magnetic force images it is shown that the exchange interaction type magnetic domains with a period of about 360 nm do exist in the BMG, which is believed to be associated with the appearance of hard-magnetic properties in this system. As the scale of the magnetic domain is much larger than the size of the short-range ordered atomic clusters existing in the BMG, it is believed that the large areas of magnetic contrast are actually a collection of a group of clusters aligned in parallel by strong exchange coupling interaction. After fully crystallization, the BMG exhibits paramagnetism. No obvious magnetic contrast is observed in the magnetic force images of fully crystallized samples, except for a small quantity of ferromagnetic crystalline phase with low coercivity and an average size of 900 nm.展开更多
Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer...Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.展开更多
Magnetic FePt nanodot arrays are promising candidates for making quantum magnetic recording disk. Here we introduce a hybrid method of FePt nanodot array fabrication through nanosphere lithography. This method combine...Magnetic FePt nanodot arrays are promising candidates for making quantum magnetic recording disk. Here we introduce a hybrid method of FePt nanodot array fabrication through nanosphere lithography. This method combines the advantages of both top-down and bottom-up approaches and does not re- quire expensive equipment nor complicated processing steps.The size of magnetic FePt nanodots prepared can be as small as 40 nm.展开更多
基金Supported in part by the National Natural Science Foundation of China,and by the Natural Science Foundation of Hebei Province.
文摘Experiments were statistically carried out on the behavior of the vertical-Bloch-line(VBL)chains of the first kind of dumbbell domains(IDs)in garnet bubble films subjected to an in-plane field,Hip.It was found that for IDs the critical in-plane field,(Hip)ID,above which their VBL chains disappear,is the same as that of ordinary hard bubbles(OHBs),H'ip.However,for IDS,the critical range of Hip for VBL chain softening is larger than that of OHBs.Besides,we also found some details of the softening process,e.g.,the collapse field range of the remaining IDs shrinks rapidly towards H_(0,mas),and this very narrow range can maintain until all IDs are softened.
文摘An experimental and theoretical study was carried out on the break-down of vertical-Bloch-line(VBL)chains in ordinary hard bubble walls subjected to an in-plane field,H_(ip).Other than a single critical value,a critical range of in-plane field,from H_(ip)^(1) to H_(ip)^(2),was found.When H_(ip)<H_(ip)^(1) the VBL chains keep unchanged;whereas when H_(ip)^(1)<H_(ip)<H_(ip)^(2),more and more hard domains are softened.Above H_(ip)^(2) all VBL chains are broken-down.A theoretical analysis showed that the critical range of H_(ip) is originated from the serpentine curving of domain walls,and a relation H_(ip)^(2)/H_(ip)^(1)=√2,was obtained,which is in good agreement with the experiments.
基金Supported In part by the National Natural Science Foundation of China.No.1880110.
文摘The“softening”process of the first kind of dumbbell domains(IDs)with the increase of temperature was experimentally revealed as follows:IDs first convert to ordinary hard bubbles(OHBs)through a partial loss of the vertical Bloch lines(VBLs)in their walls and then these OHBs convert to soft(normal)bubbles(SBs)through a further loss of VBLs.As a result,the critical temperature for the break down of VBL chains of IDs is apparently higher than OHBs.
文摘The aexercisegexperiment shows that the dumbbell domains,which can eventually contract to circular form and then collapse,should be classified as a kind of dumbbells rather than hard bubbles.Thus dumbbell domains can be divided into two kinds:ID and HD.Their static characteristics are reported,and typical photos are presented.
基金Supported in part by the National Science Foundation of China.No.19274016。
文摘The bias field dependence of the rotation direction of the dumbbells,contracted from multi-branched domains,was experimentally studied.Moreover,it was found that the rotation direction of these dumbbells can be reversed by increasing the amplitude of the testing bias pulses with quite narrow width.
基金Supported in part by the National Natural Science Foundation of China,Grant No.1880110.
文摘The self-collapse phenomenon of dumbbell domains was studied experimentally.The coincidence of the bias field region of self-collapse with that of collapse for both the first and second kinds of dumbbells manifests that two necessary conditions for self-collapse are:(1)sufficiently high number of vertical Bloch lines(VBLs)in their walls and(2)these VBLs are in high compression,and there exists the similarity between self-collapse and collapse in mechanism.
基金This work was supported by the State Key Basic I Research and Development Plan Project (Grant No. 1998010102).
文摘The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.
基金The work was supported by the National Natural Science Foundation of China (Grant Nos. 59925101 and 50031010) and the State Science and Technology Commission (Grant No. 95-yu-34).
文摘Magnetic domain structure of hard magnetic Nd60Al10Fe20Co10 bulk metallic glass (BMG) has been studied by using magnetic force microscopy. In the magnetic force images it is shown that the exchange interaction type magnetic domains with a period of about 360 nm do exist in the BMG, which is believed to be associated with the appearance of hard-magnetic properties in this system. As the scale of the magnetic domain is much larger than the size of the short-range ordered atomic clusters existing in the BMG, it is believed that the large areas of magnetic contrast are actually a collection of a group of clusters aligned in parallel by strong exchange coupling interaction. After fully crystallization, the BMG exhibits paramagnetism. No obvious magnetic contrast is observed in the magnetic force images of fully crystallized samples, except for a small quantity of ferromagnetic crystalline phase with low coercivity and an average size of 900 nm.
基金supported by the National Natural Science Foundation of China (Grant Nos.60577030,60776041,60876035)the National Key Basic Research Special Foundation of China (Grant Nos.TG2007CB307004,2006CB921607)
文摘Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.
基金Supported by the High-Tech Research and Development Program of China(GrantNo.2002AA302103)and the National Natural Science Foundation of China(GrantNo.10374110)
文摘Magnetic FePt nanodot arrays are promising candidates for making quantum magnetic recording disk. Here we introduce a hybrid method of FePt nanodot array fabrication through nanosphere lithography. This method combines the advantages of both top-down and bottom-up approaches and does not re- quire expensive equipment nor complicated processing steps.The size of magnetic FePt nanodots prepared can be as small as 40 nm.
