27 research outputs found
Observation of a Chirality-Induced Exchange-Bias Effect
Chiral magnetism that manifests in the existence of skyrmions or chiral domain walls offers an alternative way for creating anisotropies in magnetic materials that might have large potential for application in future spintronic devices. Here we show experimental evidence for an alternative type of in-plane exchange-bias effect present at room temperature that is created from a chiral 90 degrees domain wall at the interface of a ferrimagnetic-ferromagnetic Dy-Co/Ni-Fe bilayer system. The chiral interfacial domain wall forms due to the exchange coupling of Ni-Fe and Dy-Co at the interface and the presence of Dzyaloshinskii-Moriya interaction in the Dy-Co layer. As a consequence of the preferred chirality of the interfacial domain wall, the sign of the exchange-bias effect can be reversed by changing the perpendicular orientation of the Dy-Co magnetization. The chirality-created tunable exchange bias in Dy-Co/Ni-Fe is very robust against high in-plane magnetic fields (mu H-0 <= 6 T) and does not show any aging effects. Therefore, it overcomes the limitations of conventional exchange-bias systems
Magnetic and Resonant Properties of FeβBi Films
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.Film structures in the FeβBi system have been studied experimentally. The magnetic state of the two-layer structures is shown by electron magnetic resonance to be dependent on the order of depositing magnetic and nonmagnetic layers. The three-layer structures demonstrate the effect of the exchange bias, the value of which is dependent on the bismuth interlayer thickness
Magnetic resonance in FeNi/Bi/FeNi films
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.The magnetic resonance in FeNi/Bi/FeNi trilayer films with nonmagnetic semimetal spacer has been experimentally studied. It is found that the microwave absorption spectrum of samples has a complicated shape dependent on the nonmagnetic spacer thickness. In the interval of Bi layer thicknesses within 3β15 nm, the interlayer coupling has an antiferromagnetic character. Β© 2015, Pleiades Publishing, Ltd
Magnetic resonance in FeNi/Bi/FeNi films
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.The magnetic resonance in FeNi/Bi/FeNi trilayer films with nonmagnetic semimetal spacer has been experimentally studied. It is found that the microwave absorption spectrum of samples has a complicated shape dependent on the nonmagnetic spacer thickness. In the interval of Bi layer thicknesses within 3β15 nm, the interlayer coupling has an antiferromagnetic character. Β© 2015, Pleiades Publishing, Ltd
Structural and magnetic features of solid-phase transformations in Mn/Bi and Bi/Mn films
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.Solid-phase transformations at different annealing temperatures in Mn/Bi (Mn on Bi) and Bi/Mn (Bi on Mn) films have been studied using X-ray diffraction, electron microscopy, and magnetic measurements. It has been shown that the synthesis of the Ξ±-MnBi phase in polycrystalline Mn/Bi films begins at a temperature of ~120Β°C and the Mn and Bi layers react completely at 300Β°C. The resulting Ξ±-MnBi(001) samples have a large perpendicular magnetic anisotropy (Ku β 1.5 Γ 107 erg/cm3) and a coercive force H > HC ~ 3 kOe. In contrast to Mn/Bi, the ferromagnetic Ξ±-MnBi phase in Bi/Mn films is not formed even at annealing processes up to 400Β°C and Mn clusters are formed in a Bi melt. This asymmetry in phase transformations occurs because chemosorbed oxygen existing on the surface of the Mn film in Bi/Mn films suppresses a solid-phase reaction between Mn and Bi. The analysis of the results obtained implies the existence of new low-temperature (~120Β°C) structural transformation in the MnβBi system.
Π’Π²Π΅ΡΠ΄ΠΎΡΠ°Π·Π½ΡΠ΅ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΎΡΠΆΠΈΠ³Π° Π² Mn/Bi (Mn Π½Π° Bi) ΠΈ Bi/Mn ( Bi Π½Π° Mn) ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΈΡΡ Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΠ΅Π½ΡΠ³Π΅Π½ΠΎΠ²ΡΠΊΠΎΠΉ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠΈ, ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠΈΠΈ ΠΈ ΠΌΠ°Π³Π½ΠΈΡΠ½ΡΡ
ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΡΠΈΠ½ΡΠ΅Π· Π°Π»ΡΡΠ°-MnBi ΡΠ°Π·Ρ Π² ΠΏΠΎΠ»ΠΈΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΡΠ΅ΡΠΊΠΈΡ
Mn/Bi ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
Π½Π°ΡΠΈΠ½Π°Π΅ΡΡΡ ΠΏΡΠΈ ΠΏΡΠΈ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ΅ 120 Π ΠΈ ΠΏΡΠΈ 300 Π ΡΠ»ΠΎΠΈ Mn ΠΈ Bi ΡΠ΅Π°Π³ΠΈΡΡΡΡ ΠΏΠΎΠ»Π½ΠΎΡΡΡΡ. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΠΎΠ±ΡΠ°Π·ΡΡ Π°Π»ΡΡΠ°-MnBi(001) ΠΎΠ±Π»Π°Π΄Π°Π»ΠΈ Π±ΠΎΠ»ΡΡΠΎΠΉ ΠΏΠ΅ΡΠΏΠ΅Π½Π΄ΠΈΠΊΡΠ»ΡΡΠ½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠ΅ΠΉ ΠΈ Π±ΠΎΠ»ΡΡΠΎΠΉ ΠΊΠΎΡΡΡΠΈΡΠΈΠ²Π½ΠΎΠΉ ΡΠΈΠ»ΠΎΠΉ H>Hc =3 kΠ. Π ΠΎΡΠ»ΠΈΡΠΈΠ΅ ΠΎΡ Mn/Bi Π² ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
Bi/Mn Π΄Π°ΠΆΠ΅ ΠΏΡΠΈ ΠΎΡΠΆΠΈΠ³Π°Ρ
Π΄ΠΎ 400 Π‘ ΡΠ΅ΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½Π°Ρ Π°Π»ΡΡΠ°-MnBi ΡΠ°Π·Π° Π½Π΅ ΠΎΠ±ΡΠ°Π·ΠΎΠ²ΡΠ²Π°Π»Π°ΡΡ, Π° Π½Π°Π±Π»ΡΠ΄Π°Π»ΠΎΡΡ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ² Mn Π² ΡΠ°ΡΠΏΠ»Π°Π²Π΅ Bi. ΠΠ°Π½Π½Π°Ρ Π°ΡΠΈΠΌΠ΅ΡΡΠΈΡ Π² ΡΠ°Π·ΠΎΠ²ΡΡ
ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡΡ
ΠΎΠ±ΡΡΡΠ½ΡΠ΅ΡΡΡ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π² ΠΏΠ»Π΅Π½ΠΊΠ΅ Bi/Mn Π½Π° ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ Mn Ρ
Π΅ΠΌΠΎΡΠΎΡΠ±ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΊΠΈΡΠ»ΠΎΡΠΎΠ΄Π°, ΠΊΠΎΡΠΎΡΡΠΉ ΠΏΠΎΠ΄Π°Π²Π»ΡΠ΅Ρ ΡΠ²Π΅ΡΠ΄ΠΎΡΠ°Π·Π½ΡΡ ΡΠ΅Π°ΠΊΡΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ Mn ΠΈ Bi. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Π½ΡΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΡΠ΅Π΄ΠΏΠΎΠ»Π°Π³Π°Π΅ΡΡΡ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΠ΅ Π½ΠΈΠ·ΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠ³ΠΎ (120 Π‘) ΡΡΡΡΠΊΡΡΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² Mn-Bi-ΡΠΈΡΡΠ΅ΠΌΠ΅
Structural and magnetic features of solid-phase transformations in Mn/Bi and Bi/Mn films
Π’Π΅ΠΊΡΡ ΡΡΠ°ΡΡΠΈ Π½Π΅ ΠΏΡΠ±Π»ΠΈΠΊΡΠ΅ΡΡΡ Π² ΠΎΡΠΊΡΡΡΠΎΠΌ Π΄ΠΎΡΡΡΠΏΠ΅ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠΈ Ρ ΠΏΠΎΠ»ΠΈΡΠΈΠΊΠΎΠΉ ΠΆΡΡΠ½Π°Π»Π°.Solid-phase transformations at different annealing temperatures in Mn/Bi (Mn on Bi) and Bi/Mn (Bi on Mn) films have been studied using X-ray diffraction, electron microscopy, and magnetic measurements. It has been shown that the synthesis of the Ξ±-MnBi phase in polycrystalline Mn/Bi films begins at a temperature of ~120Β°C and the Mn and Bi layers react completely at 300Β°C. The resulting Ξ±-MnBi(001) samples have a large perpendicular magnetic anisotropy (Ku β 1.5 Γ 107 erg/cm3) and a coercive force H > HC ~ 3 kOe. In contrast to Mn/Bi, the ferromagnetic Ξ±-MnBi phase in Bi/Mn films is not formed even at annealing processes up to 400Β°C and Mn clusters are formed in a Bi melt. This asymmetry in phase transformations occurs because chemosorbed oxygen existing on the surface of the Mn film in Bi/Mn films suppresses a solid-phase reaction between Mn and Bi. The analysis of the results obtained implies the existence of new low-temperature (~120Β°C) structural transformation in the MnβBi system.
Π’Π²Π΅ΡΠ΄ΠΎΡΠ°Π·Π½ΡΠ΅ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΎΡΠΆΠΈΠ³Π° Π² Mn/Bi (Mn Π½Π° Bi) ΠΈ Bi/Mn ( Bi Π½Π° Mn) ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΈΡΡ Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΠ΅Π½ΡΠ³Π΅Π½ΠΎΠ²ΡΠΊΠΎΠΉ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠΈ, ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠΈΠΈ ΠΈ ΠΌΠ°Π³Π½ΠΈΡΠ½ΡΡ
ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΡΠΈΠ½ΡΠ΅Π· Π°Π»ΡΡΠ°-MnBi ΡΠ°Π·Ρ Π² ΠΏΠΎΠ»ΠΈΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΡΠ΅ΡΠΊΠΈΡ
Mn/Bi ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
Π½Π°ΡΠΈΠ½Π°Π΅ΡΡΡ ΠΏΡΠΈ ΠΏΡΠΈ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ΅ 120 Π ΠΈ ΠΏΡΠΈ 300 Π ΡΠ»ΠΎΠΈ Mn ΠΈ Bi ΡΠ΅Π°Π³ΠΈΡΡΡΡ ΠΏΠΎΠ»Π½ΠΎΡΡΡΡ. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΠΎΠ±ΡΠ°Π·ΡΡ Π°Π»ΡΡΠ°-MnBi(001) ΠΎΠ±Π»Π°Π΄Π°Π»ΠΈ Π±ΠΎΠ»ΡΡΠΎΠΉ ΠΏΠ΅ΡΠΏΠ΅Π½Π΄ΠΈΠΊΡΠ»ΡΡΠ½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠ΅ΠΉ ΠΈ Π±ΠΎΠ»ΡΡΠΎΠΉ ΠΊΠΎΡΡΡΠΈΡΠΈΠ²Π½ΠΎΠΉ ΡΠΈΠ»ΠΎΠΉ H>Hc =3 kΠ. Π ΠΎΡΠ»ΠΈΡΠΈΠ΅ ΠΎΡ Mn/Bi Π² ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
Bi/Mn Π΄Π°ΠΆΠ΅ ΠΏΡΠΈ ΠΎΡΠΆΠΈΠ³Π°Ρ
Π΄ΠΎ 400 Π‘ ΡΠ΅ΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½Π°Ρ Π°Π»ΡΡΠ°-MnBi ΡΠ°Π·Π° Π½Π΅ ΠΎΠ±ΡΠ°Π·ΠΎΠ²ΡΠ²Π°Π»Π°ΡΡ, Π° Π½Π°Π±Π»ΡΠ΄Π°Π»ΠΎΡΡ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΊΠ»Π°ΡΡΠ΅ΡΠΎΠ² Mn Π² ΡΠ°ΡΠΏΠ»Π°Π²Π΅ Bi. ΠΠ°Π½Π½Π°Ρ Π°ΡΠΈΠΌΠ΅ΡΡΠΈΡ Π² ΡΠ°Π·ΠΎΠ²ΡΡ
ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡΡ
ΠΎΠ±ΡΡΡΠ½ΡΠ΅ΡΡΡ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π² ΠΏΠ»Π΅Π½ΠΊΠ΅ Bi/Mn Π½Π° ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ Mn Ρ
Π΅ΠΌΠΎΡΠΎΡΠ±ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΊΠΈΡΠ»ΠΎΡΠΎΠ΄Π°, ΠΊΠΎΡΠΎΡΡΠΉ ΠΏΠΎΠ΄Π°Π²Π»ΡΠ΅Ρ ΡΠ²Π΅ΡΠ΄ΠΎΡΠ°Π·Π½ΡΡ ΡΠ΅Π°ΠΊΡΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ Mn ΠΈ Bi. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Π½ΡΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΡΠ΅Π΄ΠΏΠΎΠ»Π°Π³Π°Π΅ΡΡΡ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΠ΅ Π½ΠΈΠ·ΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠ³ΠΎ (120 Π‘) ΡΡΡΡΠΊΡΡΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² Mn-Bi-ΡΠΈΡΡΠ΅ΠΌΠ΅