83 research outputs found

    Direct observation of spin-quadrupolar excitations in Sr2_2CoGe2_2O7_7 by high field ESR

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    Exotic spin-multipolar ordering in spin transition metal insulators has so far eluded unambiguous experimental observation. A less studied, but perhaps more feasible fingerprint of multipole character emerges in the excitation spectrum in the form of quadrupolar transitions. Such multipolar excitations are desirable as they can be manipulated with the use of light or electric field and can be captured by means of conventional experimental techniques. Here we study single crystals of multiferroic Sr2_2CoGe2_2O7_7, and show that due to its nearly isotropic nature a purely quadrupolar bimagnon mode appears in the electron spin resonance (ESR) spectra. This non-magnetic spin-excitation couples to the electric field of the light and becomes observable for a specific experimental configuration, in full agreement with a theoretical analysis of the selection rules.Comment: 19 pages, 13 figures, , accepted for publication in Phys. Rev.

    Magnetic Resonance in the Chiral Helimagnet CrNb3S6

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    Recently, magnetic substances with chirality, namely the handedness of the magnetic structure, have attracted considerable attention because of the anomalous phenomena which appear in magnetic fields. CrNb3S6 is one of the chiral magnets formed by exchange and Dzyaloshinsky-Moriya (DM) interactions. Electron spin resonance (ESR) measurements of CrNb3S6 in magnetic fields parallel to the c-axis (helical axis) have been performed to evaluate the exchange and the DM constants that determine the helical structure. Fitting the ESR data to a calculated mode based on a spin wave theory yields values for the ferromagnetic inter-plane exchange constant J/kB = 16.2 K, the DM constant D/kB = 1.29 K, and the single-ion anisotropy constant K /kB = 1.02 K. From the Curie-Weiss temperature θCW ~ 145 K, large intra-plane ferromagnetic exchange interactions are suggested.20th International Conference on Magnetism(ICM 2015), 5th to 10th July, 2015, Barcelona, Spai

    Short-Term Effects of Acupuncture on Open-Angle Glaucoma in Retrobulbar Circulation: Additional Therapy to Standard Medication

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    Background. The relation between glaucoma and retrobulbar circulation in the prognosis has been indicated. Purpose. To investigate the effects of acupuncture on retrobulbar circulation in open-angle glaucoma (OAG) patients. Methods. Eleven OAG patients (20 eyes with OAG) who were treated by topical antiglaucoma medications for at least 3 months were enrolled. Acupuncture was performed once at acupoints BL2, M-HN9, ST2, ST36, SP6, KI3, LR3, GB20, BL18, and BL23 bilaterally. Retrobulbar circulation was measured with color Doppler imaging, and intraocular pressure (IOP) was also measured at rest and one hour after rest or before and after acupuncture. Results. The Δ value of the resistive index in the short posterior ciliary artery (P < .01) and the Δ value of IOP (P < .01) were decreased significantly by acupuncture compared with no acupuncture treatment. Conclusions. Acupuncture can improve the retrobulbar circulation and IOP, which may indicate the efficacy of acupuncture for OAG

    Cytology Reporting System for Lung Cancer from the Japan Lung Cancer Society and the Japanese Society of Clinical Cytology: An Extensive Study Containing More Benign Lesions

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    Introduction: The Japan Lung Cancer Society (JLCS) and the Japanese Society of Clinical Cytology (JSCC) have proposed a new four-tiered cytology reporting system for lung carcinoma (JLCS-JSCC system). Prior to the proposal, the Papanicolaou Society of Cytopathology (PSC) had proposed a revised reporting system (PSC system), which comprises the “neoplastic, benign neoplasm, and low-grade carcinoma” category (N-B-LG category), in addition to the 4 categories of the JLCS-JSCC system. This study aimed to evaluate the interobserver agreement of the JLCS-JSCC system with an additional dataset with more benign lesions in comparison with the PSC system. Methods: We analyzed 167 cytological samples, which included 17 benign lesions, obtained from the respiratory system. Seven observers classified these cases into each category by reviewing one Papanicolaou-stained slide per case according to the JLCS-JSCC system and PSC system. Results: The interobserver agreement was moderate in the JLCS-JSCC (k = 0.499) and PSC (k = 0.485) systems. Of the 167 samples, 17 samples were benign lesions: 7 pulmonary hamartomas, 5 sclerosing pneumocytomas, 2 squamous papillomas, one solitary fibrous tumor, one meningioma, and one lymphocytic proliferation. There were diverse sample types as follows: 11 touch smears, 3 brushing smears, 2 aspirations, and one sputum sample. Fourteen samples (82.3%) were categorized into “negative” or “atypical” by more than half of the observers in the JLCS-JSCC system. Conversely, 3 samples were categorized as “suspicious” or “malignant” by more than half of the observers in the JLCS-JSCC system. On the other hand, 11 samples (64.7%) were categorized into the N-B-LG category by more than half of the observers in the PSC system. Conclusions: The concordance rate in the JLCS-JSCC system was slightly higher than that in the PSC system; however, the interobserver agreement was moderate in both the JLCS-JSCC and PSC systems. These results indicate that both the JLCS-JSCC and PSC systems are clinically useful. Therefore, both systems are expected to have clinical applications. It may be important to integrate the 2 systems and construct a universal system that can be used more widely in clinical practice

    Anomalous spiked structures in ESR signals from the chiral helimagnet CrNb3S6

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    We have performed X-band electron spin resonance (ESR) measurements on a single crystal of the metallic chiral helimagnet CrNb3S6 from 3.5 to 180 K and for the external magnetic fields Hext , up to 4 kOe, perpendicular to the c axis (the helical axis of CrNb3S6). This field-crystalline configuration is expected to provide the chiral soliton lattice (CSL) state in this system. The main resonance line can be fit with a Dysonian function above Tc = 127 K, but additional features in the spectra were observed below 105 K. Specifically, spiked anomalies superposed on the main signals were observed for magnetic fields between Hc1 and Hc2 that are the appearing and disappearing fields of the spiked anomalies, respectively. The resulting magnetic field vs temperature phase diagram possesses three regions, which are interpreted as different dynamical responses in the CSL phase. In addition, the values of Hc2 are close to those reported by the d2M/dH2 curve [Tsuruta et al., Phys. Rev. B 93, 104402 (2016)]. Furthermore, the field range between Hc1 and Hc2, where the spiked anomalies exist, depends on the field direction and shifts to higher fields when turning to the c axis, thereby providing additional evidence that these spiked anomalies must be related to the chiral soliton dynamics

    Experimental and Theoretical Studies on Colliding Pulse Mode Locking

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