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Bismuth-doped Yttrium iron garnet (Bi:YIG) thin films known for large magneto-optical activity with low losses still need to get probed for its magnetization dynamics. We demonstrate a controlled tuning of magnetocrystalline anisotropy in Bi-doped Y3Fe5O12 (Bi:YIG) films of high crystalline quality using growth induced epitaxial strain on [111]-oriented Gd3Ga5O12 (GGG) substrate. We optimize a growth protocol to get thick highly-strained epitaxial films showing large magnetocrystalline anisotropy, compare to thin films prepared using a different protocol. Ferromagnetic resonance measurements establish a linear dependence of the out-of-plane uniaxial anisotropy on the strain induced rhombohedral distortion of Bi:YIG lattice. Interestingly, the enhancement in the magnetoelastic constant due to an optimum substitution of Bi 3+ ions with strong spin orbit coupling does not strongly affect the precessional damping (∼ 1.15 × 10 −3 ). Large magneto-optical activity, reasonably low damping, large magnetocrystalline anisotropy and large magnetoelastic coupling in BiYIG are the properties that may help BiYIG emerge as a possible material for photo-magnonics and other spintronics applications.

We report on the recrystallization of 200 nm thick as-grown Yttrium Iron Garnet ( Y 3.4 Fe 4.6 O 12 ) films on (111) face of Gadolinium Gallium Garnet (GGG) single crystals by post-deposition annealing. Epitaxial conversion of the as-grown microcrystalline YIG films was seen after annealing at 800 o C for more than 30 minutes both in ambient oxygen as well as in air. The as-grown oxygen annealed samples at 800 o C for 60 minutes crystallize epitaxially and show excellent figure-of-merit for saturation magnetization (MS = 3.3 μB/f.u., comparable to bulk value) and coercivity (HC ~ 1.1 Oe). The ambient air annealing at 800 o C with a very slow rate of cooling (2 o C/min) results in a double layer structure with a thicker unstrained epitaxial top layer having the MS and HC of 2.9 μB/f.u. and 0.12 Oe respectively. The symmetric and asymmetric Reciprocal space maps of both the samples reveal a locking of the in-plane lattice of the film to the in-plane lattice of substrate, indicating a pseudomorphic growth. The residual stress calculated by sin 2 ψ technique is compressive in nature. The lower layer in air annealed sample is highly strained, whereas, the top layer has negligible compressive stress.

Purpose:Most cases of optic neuritis are idiopathic or are associated with multiple sclerosis. We present a case in which a young female developed post-infectious left optic neuritis following herpes simplex encephalitis (HSE).Case Report:A 24-year-old female presented with a severe headache, fever, and malaise of a one-week duration. Viral encephalitis was diagnosed and treated; intravenous acyclovir (750 mg every 8 h) was administered for 14 days. The patient improved clinically and was prescribed oral valacyclovir (1,000 mg, three times daily) for an additional 3 months as an outpatient. The patient presented again four weeks after the initial admission with left periocular pain and other typical manifestations of optic neuritis. We diagnosed post-infectious left optic neuritis following viral encephalitis. Corticosteroid therapy with 250 mg intravenous methylprednisolone every 6 hours was initiated and the patient showed rapid significant recovery.Conclusion:This case report highlights the patient's clinical course and includes a brief history of the systemic effects of HSE, as well as the pathophysiology, management, and differential diagnosis of post-encephalitic optic neuritis. We suggest that clinicians should routinely perform an ophthalmologic examination during the follow-up visits of such patients.

Purpose:To present a case of deep orbital dermoid cyst with emphasis on clinical presentation, imaging spectrum, differential diagnosis and management.Case Report:A 28-year-old female was referred to our hospital with chief complaint of drooping of right eyelid and progressive headache. Ocular motility, visual acuity and fundus examination were normal. computed tomography (CT) and magnetic resonance imaging (MRI) revealed a well-defined, intraosseous deep orbital dermoid cyst (5.9 mm × 12.5 mm) located near the apex of right orbit, extending from greater wing of sphenoid into the superior orbital fissure. Due to occulomotor nerve (superior and inferior divisions) compression which passes through the superior orbital fissure, ipsilateral headache and ptosis occurred. Complete surgical excision of cyst was performed using noninvasive extracranial lateral orbitotomy approach. After removal of the cyst, curette and cutting drill were used to thoroughly remove any residual cystic content. Histopathological analysis confirmed the diagnosis. The healing was uneventful postoperatively.Conclusion:CT and MRI are easy, reliable, safe and effective imaging methods for establishing the diagnosis of orbital dermoid cyst. Size, location and manifestations are the most important determinants of the disease management. Complete surgical excision without rupture of the cyst is the treatment of choice.