Kartik Ghosh

Bio: Kartik Ghosh is an academic researcher from Missouri State University. The author has contributed to research in topics: Thin film & Pulsed laser deposition. The author has an hindex of 36, co-authored 246 publications receiving 4785 citations. Previous affiliations of Kartik Ghosh include Tata Institute of Fundamental Research & Bangabandhu Sheikh Mujib Medical University.

Critical Phenomena in the Double-Exchange Ferromagnet La 0.7 Sr 0.3 MnO 3

Abstract: We report a dc magnetization study of the critical phenomena in a high-quality single crystal of the double-exchange ferromagnet ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$. We have determined the critical temperature $({T}_{C}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}354.0\ifmmode\pm\else\textpm\fi{}0.2\mathrm{K})$ and the critical exponents, $\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.37\ifmmode\pm\else\textpm\fi{}0.04$ and $\ensuremath{\gamma}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.22\ifmmode\pm\else\textpm\fi{}0.03$. Here $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ are the critical exponents for the temperature dependence of the spontaneous magnetization just below ${T}_{C}$ and initial susceptibility just above ${T}_{C}$. Using these values of $\ensuremath{\beta}$, $\ensuremath{\gamma}$, and ${T}_{C}$, we find that the magnetization-field-temperature $(M\ensuremath{-}H\ensuremath{-}T)$ behavior below and above ${T}_{C}$ obeys scaling, following a single equation of state in which $M/({1\ensuremath{-}T/T}_{C}{)}^{\ensuremath{\beta}}$ is uniquely related to $H/({1\ensuremath{-}T/T}_{C}{)}^{\ensuremath{\beta}+\ensuremath{\gamma}}$.

Transition-element doping effects in La 0.7 Ca 0.3 MnO 3

Abstract: The influence of transition element (TE) doping on the magnetotransport properties of ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ is studied for the entire transition element series ($\mathrm{T}\mathrm{E}=\mathrm{C}\mathrm{r},$ Fe, Co, Ni, Cu, Zn) for a fixed (5% at Mn sites) dopant concentration. The systematics of different properties such as the metal-insulator transition temperature ${T}_{p},$ the Curie temperature ${T}_{c},$ $\ensuremath{\rho}{(T}_{p}),\ensuremath{\rho}(5\mathrm{K}),$ and the maximum value of magnetoresistance (MR), with respect to lattice parameter and the ionic radii of dopants, are examined. The important findings include an interesting correlation between the maximum MR, the lattice parameter, and the ionic radii, and some distinct features exhibited by Fe, Cu, and Zn dopants.

Magnetotransport anisotropy effects in epitaxial magnetite (Fe 3 O 4 ) thin films

Abstract: Epitaxial films of magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ have been grown on ${\mathrm{SrTiO}}_{3}$ (100) and sapphire (\ensuremath{\alpha}-${\mathrm{Al}}_{2}{\mathrm{O}}_{3},$ 0001) substrates by pulsed laser deposition, and they exhibit crystal orientations of [100] and [111], respectively. Films of both orientations show a clear Verwey transition near 120 K. The temperature dependence of magnetoresistance of the films is examined at fields up to 8.5 T applied parallel to the film plane. The [100] oriented films show a pronounced extremum in magnetoresistance (MR) at the Verwey transition temperature ${(T}_{v}),$ while no such feature is observed in the case of the [111] oriented films. However, the [111] oriented films exhibit a sudden change in the MR dependence on $T$ at ${T}_{v}$ and films of both orientations show a rapid increase of MR as the temperature is decreased below about 110 K. An attempt is made to analyze these data in terms of the known anisotropy in magnetostriction and optical magnon-phonon dispersions, and the small polaron band and hopping conductivity mechanisms.

Effect of crystallinity on the magnetoresistance in perovskite manganese oxide thin films

Abstract: We report our study of the effect of crystallinity on the magnetoresistance in epitaxial and polycrystalline La2/3Ba1/3MnO3 and La2/3Ca1/3MnO3 thin films. Magnetoresistance in epitaxial films exhibits field dependence and temperature dependence similar to bulk single crystals and sintered bulk ceramics. The polycrystalline films exhibit a markedly different behavior. The magnetoresistance in this case shows either a monotonic increase or saturation with decreasing temperature in contrast to that of epitaxial films in which the magnetoresistance peaks close to the ferromagnetic transition temperature. The field dependence in the polycrystalline films is also remarkably different. At low fields, we observe a sharp drop in resistance followed by a more gradual decrease at higher fields. Our data suggest that in addition to the intrinsic magnetoresistance, grain-boundary transport contributes significantly to the magnetoresistance in polycrystalline films.

Structure and magnetic order in La 1 − x Ca x MnO 3 ( 0 x 0 . 3 3 )

Abstract: The nuclear and magnetic structures of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ have been studied by neutron powder diffraction methods for the compositions $x=006,$ 015, 0175, 025, and 033 At low concentrations of Ca $(x=006)$ the oxidized sample contains cation vacancies and the structure is ferromagnetic, while in reduced samples all atomic sites are fully occupied and the structure is antiferromagnetic This result explains the discrepancies found in published phase diagrams In the samples with compositions $xg~015,$ the structural distortions associated with the magnetic and electronic transitions increase with increasing Ca content These distortions consist mainly of an increase in the tilting of the ${\mathrm{MnO}}_{6}$ octahedra and a consequent sharp decrease of the Mn-Mn separations as the system becomes metallic and ferromagnetic These readjustments of the structure may be responsible for the metallic character of the bonds at the transition from insulating to metallic behavior The magnetic-field dependence of the lattice parameters, studied in sample $x=033$ at two fixed temperatures (270 and 240 K), demonstrates that there is strong coupling between the magnetization and the structural properties in this system

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Ferromagnetic materials

Abstract: In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

X-Ray Diffraction

Abstract: Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

Campbell-Walsh urology

Abstract: Section I: Anatomy Surgical Anatomy of the Retroperitoneum, Kidneys, and Ureters Anatomy of the Lower Urinary Tract and Male Genitalia Section II: Clinical Decision Making Evaluation of the Urologic Patient: History, Physical Examination, and Urinalysis Urinary Tract Imaging: Basic Principles Outcomes Research Section III: Basics of Urologic Surgery Basic Instrumentation and Cystoscopy Basics of Laparoscopic Urologic Surgery Section IV: Infections and Inflammation Infections of the Urinary Tract-A. Schaeffer Inflammatory Conditions of the Male Genitourinary Tract Interstitial Cystitis and Related Disorders Sexually Transmitted and Associated Diseases Urological Implications of AIDS and Related Conditions Cutaneous Diseases of the External Genitalia Tuberculosis and Other Opportunistic Infections of the Genitourinary System Section V: Molecular and Cellular Biology Basic Principles of Immunology Molecular Genetics and Cancer Biology Tissue Engineering Perspectives for Reconstructive Surgery Section VI: Reproductive and Sexual Function Male Reproductive Physiology Male Infertility Surgical Management of Male Infertility Physiology of Erectile Dysfunction: Pathophysiology, Evaluation, Nonsurgical Management Epidemiology, Evaluation, and Nonsurgical Management of Erectile Dysfunction Prosthetic Surgery for Erectile Dysfunction Vascular Surgery for Erectile Dysfunction Peyronie's Disease Priapism Androgen Deficiency in the Aging Male Female Sexual Function and Dysfunction Section VII: Male Genitalia Neoplasms of the Testis Surgery of Testicular Tumors Tumors of the Penis Surgery of Penile and Urethral Carcinoma Surgery of the Penis and Urethra Surgery of the Scrotum and Seminal Vesicles Section VIII: Renal Physiology and Pathophysiology Renal Physiology and Pathophysiology Renovascular Hypertension Section IX: Upper Urinary Tract Obstruction and Trauma Pathophysiology of Obstruction Management of Upper Urinary Tract Obstruction Upper Urinary Tract Trauma Section X: Renal Failure and Transplantation Renal Transplantation Etiology, Pathogenesis, and Management of Renal Failure Section XI: Urinary Lithiasis and Endourology Urinary Lithiasis: Etiology, Epidemiology, and Pathophysiology Evaluation and Medical Management of Urinary Lithiasis Surgical Management of Upper Urinary Tract Calculi Ureteroscopy and Retrograde Ureteral Access Percutaneous Approaches to the Upper Urinary Tract Section XII: Neoplasms of the Upper Urinary Tract Renal Tumors Urothelial Tumors of the Upper Urinary Tract Urothelial Tumors of the Renal Pelvis and Ureter Open Surgery of the Kidney Laparoscopic Surgery of the Kidney Ablative Therapy for Renal Tumors Section XIII: The Adrenals Pathophysiology, Evaluation, and Medical Management of Adrenal Disorders Surgery of the Adrenals Section XIV: Urine Transport, Storage, and Emptying Physiology and Pharmacology of the Renal Pelvis and Ureter Physiology and Pharmacology of the Bladder and Urethra Pathophysiology, Categorization, and Management of Voiding Dysfunction Urodynamic and Video dynamic Evaluation of Voiding Dysfunction Neuromuscular Dysfunction of the Lower Urinary Tract Urinary Incontinence: Epidemiology, Pathophysiology, Evaluation, and Overview of Management The Overactive Bladder Pharmacologic Management of Storage and Emptying Failure Conservative Management of Urinary Incontinence: Behavioral and Pelvic Floor Therapy, Urethral and Pelvic Devices Electrical Stimulation and Neuromodulation in Storage and Emptying Failure Retropubic Suspension Surgery for Incontinence in Women Vaginal Reconstructive Surgery for Sphincteric Incontinence Pubovaginal Slings Tension-Free Vaginal Tape Procedures Injection Therapy for Urinary Incontinence Additional Treatment for Storage and Emptying Failure Geriatric Voiding Dysfunction and Urinary Incontinence Urinary Tract Fistulae Bladder and Urethral Diverticula Surgical Procedures for Sphincteric Incontinence in the Male: The Artificial Genitourinary Sphincter Perineal Sling Procedures Section XV: Bladder Lower Genitourinary Calculi and Trauma Urothelial Tumors of the Bladder Management of Superficial Bladder Cancer Management of Metastatic and Invasive Bladder Cancer Surgery of Bladder Cancer Laparoscopic Bladder Surgery Use of Intestinal Segments in Urinary Diversion Cutaneous Continent Urinary Diversion Orthotopic Urinary Diversion Genital and Lower Urinary Tract Trauma Lower Urinary Tract Calculi Section XVI: Prostate Molecular Biology, Endocrinology, and Physiology of the Prostate and Seminal Vesicles Etiology, Pathophysiology, and Epidemiology of Benign Prostatic Hyperplasia Natural History, Evaluation, and Nonsurgical Management of Benign Prostatic Hyperplasia Minimally Invasive and Endoscopic Management of Benign Prostatic Hyperplasia Retropubic and Superpubic Open Radical Prostatectomy Epidemiology, Etiology, and Prevention of Prostate Cancer Pathology of Prostatic Neoplasms Ultrasonography and Biopsy of the Prostate Tumor Markers in Prostate Cancer Early Detection, Diagnosis, and Staging of Prostate Cancer Definitive Therapy of Localized Prostate Cancer: Outcomes Expectant Management of Prostate Cancer Anatomic Retrograde Retropubic Prostatectomy Radical Perineal Prostatectomy Laparoscopic and Robotic Radical Prostatectomy and Pelvic Lymphadenectomy Radiation Therapy for Prostate Cancer Cryotherapy of Prostate Cancer Treatment of Locally Advanced Prostate Cancer Management of Rising Prostate-Specific Antigen after Definitive Therapy Hormonal Therapy for Prostate Cancer Management of Hormone-Resistant Prostate Cancer Section XVII: Pediatric Urology Normal and Anomalous Development of the Urinary Tract Renal Function in the Fetus Congenital Obstructive Uropathy Perinatal Urology Evaluation of Pediatric Urologic Patient Renal Disease in Childhood Urinary Tract Infections in Infants and Children Anomalies of the Kidney Renal Dysplasia and Cystic Disease of Kidney Anomalies and Surgery of the Ureteropelvic Junction Ectopic Ureter Vesicoureteral Reflux Prune-Belly Syndrome Exstrophy and Epispadias Complex Surgical Technique for One-Stage Exstrophy Reconstruction Bladder Anomalies in Children Posterior Urethral Valves and Other Urethral Anomalies Voiding Dysfunction in Children: Neurogenic and Non-neurogenic Urinary Tract Reconstruction Hypospadias Abnormalities of External Genitalia in Boys Abnormalities of Testis and Scrotum: Surgical Management Sexual Differentiation: Normal and Abnormal Surgical Management of Intersex Pediatric Oncology Pediatric Endourology and Laparoscopy Pediatric Genitourinary Trauma