Magneto-optical Applications Research Articles

High magnetic susceptibility-based vanadate tellurite glasses for magneto-optical device applications

Tellurite glasses modified with V2O5, Fe2O3, and Na2O (TVFN), along with Sm3+-doped Gd2O3 and Sb2O3 based tellurite (TVGSNSm) glasses evaluated for various properties. The thermal stability of these glasses, with a critical value of 105 °C advantageous to luminescence. Fourier transform infrared and micro-Raman bands were identified at 669, 745, 859, 943, and 1003 cm−1 in the deconvolution. Electron spin resonance revealed a signal at a magnetic field of 340.75 mT (g = 1.77). The magnetic hysteresis of TVFN glasses from a vibrating sample magnetometer which possess coercivity 62 mT and remanence 1.5х10−2 Am2/kg with a saturation magnetization 0.1975 A m2/kg and magnetic susceptibility as high as 0.1328. The magnetic nature confirmed by superconducting quantum interference device. Photoluminescence of Sm3+-doped TVGSNSm glasses excited by 408 nm showed 646 nm (red-orange) dominated emission band over the 603 nm band. These findings underscore the potential of TVFN glasses for applications in magneto-optical devices.

Магнито-оптическая чувствительность spun-волокна при наличии осевого механического скручивания

The polarization state of light radiation in a spun fiber is one of the factors determining its magneto-optical sensitivity and application in current sensors. In the article, the effect of elastic twisting around the spun fiber axis on the evolution of radiation polarization and the sensitivity of the fiber is studied by modeling. It has been found that twisting effects or other effects that change the spiral pitch lead to degradation of the sensitivity of the spun fiber, and the amount of degradation is determined by the state of polarization at the input of the disturbed fiber section. It is shown that when returning to the non-stressed state with the initial parameters, the sensitivity of the fiber does not recover, but continues to decrease. The importance of minimizing twisted sections in the practical application of spun fiber in a current sensor is noted.

Spin chain orientation and magneto-optical coupling in twisted NiPS3 homostructures

Magnetic two-dimensional (2D) materials have garnered significant attention due to their unique electronic, magnetic, and optical properties and their potential applications in next-generation electronic and optoelectronic devices. However, the magneto-optical effects of oligolayer antiferromagnetic materials remain inadequately understood. Here, we investigate the magnetic properties of few-layer nickel phosphorus trisulfide (NiPS3) and its twisted heterostructures, emphasizing the observation of optical phenomena at low temperatures (1.65 K). By stacking few-layer NiPS3 to fabricate twisted homostructures, we probe their magnetic characteristics using photoluminescence (PL) spectroscopy. Our results reveal that sharp exciton peaks emerge at low temperatures and that the spin chain orientation in oligolayer NiPS3 can be discerned through the polarization dependence of exciton PL intensity. Notably, fewer-layered NiPS3 exhibits a significant magneto-optical effect under an applied magnetic field, allowing the modulation of the polarization angle of its exciton PL spectrum. Additionally, the polarization-dependent Raman spectrum of NiPS3 shows substantial changes under the influence of a magnetic field. These findings underscore the potential of few-layer NiPS3 for future magneto-optical device applications.

Investigating the influence of cerium doping on the structural, optical and electrical properties of ZnNiMgFe2-xCexO4 soft ferrites

The present work reports the optical, structural, and electrical properties of cerium-doped Zn0.6Ni0.2Mg0.2Fe2-xCexO4 soft ferrites by green synthesis method that unwrap transformative insights and find technological applications through X-ray diffraction (XRD), UV visible spectroscopy and IV-point probe techniques. Ferrites with different cerium concentrations (x = 0.0, 0.0250, 0.0375) show an enormous difference in the optical, structural, and electrical behavior of the ferrites. The crystallite size increases to 46.9 nm, with a concomitant increase in lattice constants up to 8.550 Å for x = 0.0375. A similar structural shift was noticed in X-ray and bulk densities from 5.031 to 4.982 g/cm³ and 3.83 to 3.97 g/cm³, respectively. The optical explorations revealed a remarkable bandgap reduction from 2.768 eV to 2.758 eV improving the utility of the material substantially in magneto-optic devices. Conversely, the refractive index increases from 2.420 to 2.423, and the imaginary dielectric constant goes up from 10.654 to 10.667, giving a herald of advancement in photonic technologies. Electrically, the study marks a drastic reduction in DC resistivity from 1.95 × 105 to 6.13 × 103 ohm-cm with the Ce doping, which indicates higher conductivity suitable for telecommunication. This extensive work on Ce-doped soft ferrites now opens up newer avenues of applications in electronics and magneto-optics, blending scientific inquiry with practical utility.

Structural, morphological, optical, electrical, and magnetic properties of aluminum-doped CoxCa(0.90−x)Ni0.10Fe2O4 flexible substrate for visible to NIR spectra applications

This paper presents a conductive component tailored to a flexible substrate using Al-doped CoxCa(0.90−x)Ni0.10Fe2O4 (x = 0.25, 0.50, and 0.75) for visible to near-infrared (NIR) spectra in magneto-optical applications. The developed nanoparticles show uniformity, nanosized grains, and capillary nanopore fusion characteristics, which are confirmed by x-ray diffraction (XRD), field emission scanning electron microscopy, and energy-dispersive x-ray spectroscopy analyses, respectively. The XRD analysis revealed crystallite sizes of 33.36, 37.08, and 44.25 nm and particle sizes of 45.6, 34.6, and 31.5 nm for the compositions x = 0.25, 0.50, and 0.75, respectively. The Al-doped nanoparticles are converted to a flexible solid substrate utilizing a polyvinyl alcohol matrix, facilitating conformality to build complex shapes and broadening their application scope. The structure shows higher absorption across 450–720 nm, 480–720 nm, and 200–850 nm spectra for x = 0.25, 0.50, and 0.75, respectively. The distinctive magnetic and electrical properties are also evaluated through magnetic force microscopy and conductive atomic force microscopy, culminating in a substrate with exceptional control over light–matter interactions with smooth surfaces with lower surface roughness. The vibrating sample magnetometer analysis of the substrate shows how varying cobalt content affects magnetic properties relevant for visible to near-infrared (NIR) applications, offering insights into coercivity, magnetization, and retentivity changes at different x values. The perceptible novelties of this work are advancements in material sciences aimed at enhancing light manipulation and flexibility for electronic devices.

Manipulation of energy-resolved magneto–optical effect in yttrium iron garnet films achieved by covering with nonmagnetic metals

The effect of the interface-driven magnetic optical (MO) manipulation on Pt/Yttrium iron garnet (YIG) and Cu/YIG has been investigated using energy-resolved magnetic circular dichroism (ER-MCD) system. By mapping the spatial MCD at different excitation energies, the results indicate manipulation of the spin-polarized electronic structure of YIG through interface charge transfer. Specifically, compared to the Cu/YIG region, we found that the Pt/YIG region exhibited a higher level of MCD enhancement and even a pronounced MCD sign inversion at certain excitation energies. In contrast, the saturation moment of the Pt-covered YIG film decreased significantly, while the enhancement was only slight for the Cu-covered YIG film. Based on the first-principles calculations, the presence of distinct polarized interface states of tetrahedral Fe ions in metal/YIG systems results in conflicting observations regarding optical and magnetic proximity effects. We present evidence that ER-MCD can effectively reveal dominant spin-polarized optical transitions in ferrimagnetic (FIM) materials, providing direct access to the polarized interface states in the nonmagnetic metal (NM)/FIM heterosystem. This capability opens opportunities to manipulate and customize the magneto–optical effect with energy resolution for various applications in magneto-optics.

Functionalization of micro-size garnet at the end of optical fiber for magneto-optical applications

We utilized a metal propionate solution to prepare polycrystalline bismuth-substituted yttrium iron garnets through the metal-organic decomposition process. After conducting thorough optimization, we successfully synthesized a garnet that exhibited a high magneto-optic response directly at the end of an optical fiber. A notable achievement of our work lies in the ability to restrict the size and position of the garnet to match the dimensions of the fiber's core. The functionalized fiber was integrated into a magneto-optical sensor setup, offering the flexibility to operate either in the Faraday rotation or magnetic circular dichroism mode.

Enhanced inverse Faraday effect and time-dependent thermo-transmission in gold nanodisks

Abstract Nonmagnetic media can be magnetized by light via processes referred to as an inverse Faraday effect (IFE). With nonmagnetic metal nanostructures, the IFE is dominated by the presence of light-induced solenoidal surface currents or plasmons with orbital angular momenta, whose properties depend on both the light and nanostructure geometry. Here, through a systematic study of gold nanodisks with different sizes, we demonstrate order-of-magnitude enhancement of the IFE compared to a bare gold film. Large IFE signals occur when light excites the dipolar plasmonic resonance of the gold nanodisk. We observe that the spectral response of the IFE signal mirrors the spectral response of time-dependent thermo-transmission signals. Our careful quantitative experimental measurements and analysis offer insight into the magnitude of IFE in plasmonic structures for compact, low-power, magneto-optic applications.

DFT insights into LaFeO3 with Mn substitution: A promising path to energy-efficient magneto-optical applications.

In recent years, the demand for electronic materials has significantly increased, driven by industrial needs and the pursuit of cost-efficient alternatives. This comprehensive study investigates the effects of Mn substitution on LaFeO3 through the implementation of the GGA approach in density functional theory. The research findings demonstrate remarkable consistency with the experimental outcomes reported in the existing literature pertaining to the studied compounds. However, this study unveils novel insights into the mechanical and optical characteristics of the doped structures, which have not been previously reported. The structural stability is rigorously examined through multiple stability criteria, encompassing structural optimization, tests of elastic stability, and enthalpy of formation calculations. Furthermore, the electronic and optical properties of the compounds exhibit exceptional improvements in conductivity and reflectivity as a result of the doping process. The band structure analysis reveals the presence of a Moss-Burstein shift. Investigation of the magnetic properties indicates an increase in the magnetic moment value due to the Fe-Mn degeneracy resulting from increased Mn content. Mechanical analysis of the elastic moduli B, G, and Y demonstrates an enhanced strength and metal-like conductivity, attributed to the induced anharmonicity. Moreover, the internal strain factor suggests a higher degree of bond flexibility, implying potential applications of these compounds in flexible electronics.

Magnetic and magneto-optical properties of manganese-containing antimony phosphate glasses – An alternative to Faraday rotators

Glasses in system 100-x(70SbPO4–10ZnO–20PbO) xMnO, with x = 0, 10, 20 and 30 mol %, where prepared by the conventional melting-quenching method. The glasses were cut, polished and characterized by XRD, DSC, Raman, FTIR, UV–Vis and luminescence and magnetic and magneto-optical aiming application ultimate as in magneto-optical devices. These samples containing manganese exhibit magnetic response to neodymium magnets at room temperature. In addition, they feature thermal stability above 100 °C, wide transparency in the visible and near infrared region. The optical absorption spectra of the glass revealed the presence of characteristic absorption bands of Mn2+ at 410 nm attributed to 6A1(S) → 4A1, 4E (4G) transition and possible oxidation at around 550 nm assigned to 5B1g → 5B2g transition of the Mn3+ ions. Refractive indices higher than 1.8 and characteristic emission bands around 680–720 nm, assigned to 4T1(G)→6A1(S) transition, were also observed. Magnetic susceptibility measurements revealed the paramagnetic character of the Mn-containing glasses, with antiparallel spin alignment. Finally, a linear growth trend was observed for the Verdet constant along with the Mn2+ concentration and the highest value measured, for sample containing 30 mol% of MnO, was −55.1 ± 3.2 rad T−1 m−1 at 632.8 nm. This value is close to those of some families of glasses containing rare earths, being an alternative of new low-cost magneto-optical vitreous materials.

Structural, Optical and Magnetic Properties of (1−x) YFeO3 + (x) Sr2Bi4Ti5O18 (where 0 ≤ x ≥ 0.005) Nanomaterials

Continuous efforts are being made on YFeO3 (YFO) nanomaterial to improve the magnetization value in different ways for photocatalysis and magneto-optical application point of view because of low energy bandgap (1.8–2.8 eV). In this regard, we made solid solutions with Sr2Bi4Ti5O18 (SBT) nanomaterial in an effort to increase the magnetization value of YFO nanomaterial. Here prepared the (1−x) YFO + x SBT (where x = 0, 0.00125, 0. 0025, and 0.005) nanomaterials via sol-gel route, and thus obtained individually powders were calcined at 1050 °C/3 h. The single phase of YFO without any unreacted or impurity phases were observed up to x = 0.25 mol% via X-ray diffraction studies. Calculated average crystallite size as well as dislocation density suggesting that the improvement of crystalline nature YFO sample with an increase of SBT content in YFO. The improved magnetization value (4.121 emu g−1), which is 1.3 times higher than that of YFO (3.188 emu g−1), for the x = 0.25 mol% SBT in YFO was observed, however their coercivity (39.4 Oe) is almost similar for both samples. The computed optical bandgap was found to be reduced with an increase of SBT mol% in YFO. We draw the conclusion from this analysis that SBT in YFO (x = 0.25 mol%) will make promising candidates for various magnetic applications.

Structure, property and magneto-optical interaction of wide-band-gap layered magnetism near the Néel temperature with antiferromagnetic to paramagnetic transition

This work reports structural, optical, and vibrational behaviors, revealing the Néel ordering transformation of MnPS3 via temperature-dependent structure and optical measurements. In antiferromagnetic (AFM) state, MnPS3 exhibits high magnon-phonon coupling due to the ordered spin in the 3d orbital of the Mn2+ cation, which influences the intrinsic lattice and vibrational properties. The band-edge excitons of thin-layered MnPS3 were detected via micro-thermoreflectance (μTR) measurements at 20–300 K. When below the Néel temperature (TN = 78 K), MnPS3 exhibits two excitons, indicating the availability of a magnetic transition from the AFM to paramagnetic (PM) ordering. The direct-gap exciton of MnPS3 (E1OX) is at ∼ 2.632 eV at 300 K and it shifts to a higher energy of ∼ 2.846 eV at 20 K. With T < TN, an additional exciton (AMX) appeared at ∼ 0.16 eV lower than E1OX. It shows stronger at 20 K. The E1OX feature can be observed by μTR, and it shows an anomalous temperature-intensity change with the maximum amplitude at TN due to the spin-order transition from the AFM to the PM state. This work explores optical properties related to the magnetic transition of a wide-band-gap layered magnetism, which may be suitable for further magneto-optical device applications.

Optically controlled ultrafast dynamics of skyrmion in antiferromagnets

The optical vortex, an optical beam carrying orbital angular momentum (OAM), has been demonstrated to be promising in manipulating magnetic structure and its dynamics in various systems. In this work, by using numerical and analytical methods, we investigate the optical vortex control of the ultrafast dynamics of skyrmion in antiferromagnets. It is shown that an isolated skyrmion can be generated/erased in an ultrashort time of $\ensuremath{\sim}\mathrm{ps}$ by beam focusing through the Zeeman effect. Subsequently, the OAM can be transferred to the skyrmion and results in its rotation. Different from the case of ferromagnets, the skyrmion rotation direction in antiferromagnets depends on the light frequency, allowing an easy control of the skyrmion rotation via tuning the frequency of light beam. Furthermore, the skyrmion Hall motion, driven by multipolar spin waves that are excited by optical vortex, is revealed in our calculations, demonstrating the dependence of the Hall angle on the OAM quantum number. This work unveils the interesting optical control of the skyrmion dynamics in antiferromagnets, which is a crucial step towards the development of magneto-optic and spintronic applications.

Frequency-dependent Faraday and Kerr rotation in anisotropic nonsymmorphic Dirac semimetals

We calculate the frequency-dependent longitudinal and Hall conductivities and the Faraday and Kerr rotation angles for a single sheet of anisotropic Dirac semimetal protected by nonsymmorphic symmetry in the presence of a Zeeman term coupling to the out-of-plane component of the spin. While the Zeeman term causes a rotation of the plane of polarization of the light, the anisotropy causes the appearance of an elliptically polarized component in an initially linearly polarized beam. The two effects can be combined in a single complex Faraday rotation angle. At the zero-frequency limit, we find a finite value of the Faraday rotation angle, which is given by $2{\ensuremath{\alpha}}_{F}$, where ${\ensuremath{\alpha}}_{F}$ is the effective fine structure constant associated with the velocity of the linearly dispersing Dirac fermions. We also find a logarithmic enhancement of the Faraday (and Kerr) rotation angles as the frequency of the light approaches the absorption edge associated with the Zeeman-induced gap. While the enhancement is reduced by impurity scattering, it remains significant for an attainable level of material purity. These results indicate that two-dimensional Dirac materials protected by nonsymmorphic symmetry are responsive to Zeeman couplings and can be used as platforms for magneto-optic applications, such as the realization of polarization-rotating devices.

Anomalous ferromagnetism and magneto-optic Kerr effect in rare-earth substituted Na0.5Bi0.5TiO3

Designing multifunctional materials with prominent electrical, optical, and magnetic properties is of keen interest to many technological applications. In the roadmap for designing such materials, we have investigated the rare-earth (Nd and Er)-substituted NBT using first-principles calculations. Our calculation predicts the emergence of magnetic degrees of freedom in these materials. The magnetic moments obtained, for the largest concentration of 25%, are ≈1.47 and 1.49 μB/f.u., respectively, for Nd-NBT and Er-NBT. The mechanism for nonzero magnetic moments in (Nd/Er)-NBT is traced to the presence of unpaired f-electrons in the systems. Our simulations on magneto-optic effects show a significant Kerr signal of 0.7 ° in both the materials. This suggests rare-earth substituted NBT as potential candidates for magneto-optical applications and motivates more theoretical and experimental works along this direction.

Probing the Néel-Type Antiferromagnetic Order and Coherent Magnon-Exciton Coupling in Van Der Waals VPS3.

2D van der Waals (vdW) antiferromagnets have received intensive attention due to their terahertz resonance, multilevel magnetic-order states, and ultrafast spin dynamics. However, accurately identifying their magnetic configuration still remains a challenge owing to the lack of net magnetization and insensitivity to external fields. In this work, the Néel-type antiferromagnetic (AFM) order in 2D antiferromagnet VPS3 with the out-of-plane anisotropy, which is demonstrated by the temperature-dependent spin-phonon coupling and second-harmonic generation (SHG), is experimentally probed. This long-range AFM order even persists at the ultrathin limit. Furthermore, strong interlayer exciton-magnon coupling (EMC) upon the Néel-type AFM order is detected based on the monolayer WSe2 /VPS3 heterostructure, which induces an enhanced excitonic state and further certifies the Néel-type AFM order of VPS3 . The discovery provides optical routes as the novel platform to study 2D antiferromagnets and promotes their potential applications in magneto-optics and opto-spintronic devices.

Praseodymium-dopant effect on bismuth-substituted yttrium iron garnet films on fused silica glass substrate at the 1310 and 1550-nm wavelengths

The optical and magneto-optic (MO) properties of the praseodymium (Pr)-dopant effect on bismuth-substituted yttrium iron garnet (Bi:YIG) films coated on fused silica glass substrates by using the metal-organic-decomposition (MOD) method with chemical solutions were investigated at the 1310 and 1550-nm wavelength regions. The maximum Faraday rotation angle of the Pr-codoped Bi:YIG (Pr,By:YIG) film was observed to be 0.09 and 0.046 deg/μm at the wavelengths of 1310 and 1550 nm, respectively, when the film was annealed at a temperature of 750 °C, while those of the plain Bi:YIG film were 0.059 and 0.039 deg/μm. More than 50% improvement in the Faraday rotation value of the Pr,Bi:YIG film was observed compared to that of the Bi:YIG film at the 1310 nm wavelength. The absorption coefficient of the Pr,Bi:YIG film was comparable to that of the Bi:YIG film. Therefore, the Pr,Bi:YIG film prepared with the MOD method is potentially useful for MO applications such as optical isolators and circulators.

Novel Nd3+ and Ho3+ co-doped multifunctional CeF3 crystal for laser and magneto-optical applications

In this study, a 1.5 at.% Nd3+ and 0.5 at.% Ho3+ co-doped CeF3 (Nd,Ho:CeF3) single crystal was successfully grown by the vertical Bridgman method. The absorption and fluorescence characteristics of the fabricated crystal were evaluated. The spectroscopic properties of the Nd,Ho:CeF3 crystal were investigated based on the Judd–Ofelt (J–O) theory. The parameters Ω2, Ω4, and Ω6 of Ho3+ were fitted as 0.338 × 10−20, 0.731 × 10−20, and 0.350 × 10−20 cm2, respectively. The fluorescence lifetimes centered at 1064 and 1970 nm for Nd3+ and Ho3+ were 261 and 47 μs, respectively. Notably, the magneto-optical performance of the Nd,Ho:CeF3 crystal was investigated for the first time. The measured Verdet constants of Nd,Ho:CeF3 at 532, 632.8, 1064, 1310, and 1550 nm were 228.0, 154.7, 42.4, 29.1, and 18.5 rad·T−1·m−1, respectively, which were significantly larger than those of pure CeF3 and traditional Tb3Ga5O12. The results demonstrated that Nd,Ho:CeF3 crystals can be applied in both lasers and magneto-optical devices.

The influence of spin state of the Cr ions on the structural and magnetic behavior of orthorhombic LaFe1−xCrxO3 Perovskites (0.0

Herein, we report, for the first time, the influence of the state of spin of the Cr3+ ions on the structure and magnetic behavior of LaFe1−xCrxO3 (0.0 < x < 0.5) perovskite crystal structures to improve their magnetic properties for memory storage and magneto-optical application potential. A series of LaFe1−xCrxO3 (0.0 < x < 0.5) nanocrystals was prepared using the citrate-nitrate auto-combustion route. The influence of the Cr3+ ions on the structure and morphology of the LaFe1−xCrxO3 nanostructures was emphasized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), the selected area of electron diffraction (SAED), and scanning electron microscopy (SEM). The results revealed that the inclusion of the Cr3+ ions into the Fe3+ sites leads to an increase in the crystallite size of the LaFe1−xCrxO3 (0.0 < x < 0.5) nanocrystals, from 16.12 to 57.29 nm, to preserve their orthorhombic crystal symmetry. The phase stability and the electron density mapping of the prepared orthoferrite nanocrystals were verified using the Goldschmidt tolerance factor and Rietveld refinement. The magnetic properties were evaluated and discussed based on Kanamori–Goodenough (KG) regulations and Heisenberg Hamiltonian notation. The results showed that the inclusion of the 20 mol% of Cr3+ ions in the Fe sites results in an enhancement of the magnetic parameters. The enhancement of the magnetic behavior was argued to the tendency of the Cr3+ ions to be in the high spin state when included in the Fe3+ ions site. This improvement in the magnetic performance of the LaFe1−xCrxO3 (x = 0.2) nanocrystals will open a new avenue for using this nanomagnetic material in the fields of memory storage and magneto-optical devices.

Elucidating the Mn2+ Dopant Sites in Two-Dimensional Na–In Halide Perovskite

The layered hybrid double perovskites (LDPs) possess excellent stability and environmental friendliness, which makes them remarkable semiconducting materials. Contrary to significant advancements, the nonfluorescent nature at ambient temperature and pressure is still a major hurdle in this intriguing family. Here, we demonstrate doping of the transition metal cation Mn2+ in two-dimensional (2D) (PEA)4NaInCl8 (PEA = phenylethylamine) LDP, by a solution-processed crystallization method. This results in broadband emission at ambient conditions and initial contraction followed by expansion of host lattice on increasing dopant concentration. A higher dopant feed ratio in this wide band gap material leads to the absorption at 2.95 eV due to the 6A1 (6S) → 4A1 (4G) transitions on Mn2+ centers. First-principles calculations based on density functional theory (DFT) confirm that Mn2+ in substitutional sites results in lattice contraction while interstitial site Mn2+ doping leads to lattice expansion. The potential of Mn2+ to improve optical and magnetic properties of host lattice and a deeper understanding of distribution of Mn2+dopant make these LDPs a promising material for emitters for solid-state lighting and magneto-optical applications.