Superconducting properties of thin film <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>Nb</mml:mi> </mml:mrow> <mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mi>x</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>Ti</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>x</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> N studied via the NMR of implanted <sup>8</sup>Li
Bibliographic record
Abstract
Abstract We report measurements of the normal-state and superconducting properties of thin-film <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext>Nb</mml:mtext> <mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mi mathvariant="normal">x</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext>Ti</mml:mtext> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">x</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> N using 8 Li β -detected nuclear magnetic resonance ( β -NMR). In these experiments, radioactive 8 Li + probes were implanted ∼21 nm below the surface of a Nb 0.75 Ti 0.25 N(91 nm) film in Nb 0.75 Ti 0.25 N(91 nm)/AlN(4 nm)/Nb and its NMR response recorded (via 8 Li’s β -emissions) between 4.6 K and 270 K in a 4.1 T field applied normal to its surface. Resonance measurements reveal wide, symmetric lineshapes at all temperatures, with significant additional broadening below the film’s superconducting transition temperature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi mathvariant="normal">T</mml:mi> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>15.4</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mn>7</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi mathvariant="normal">K</mml:mi> </mml:mrow> </mml:mrow> </mml:math> due to vortex lattice formation. Fits to a broadening model find a magnetic penetration depth <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>λ</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">K</mml:mi> </mml:mrow> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>180.57</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mn>30</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi>nm</mml:mi> </mml:mrow> </mml:mrow> </mml:math> and upper critical field <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">K</mml:mi> </mml:mrow> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>18</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mn>4</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi mathvariant="normal">T</mml:mi> </mml:mrow> </mml:mrow> </mml:math> , consistent with literature estimates. Spin-lattice relaxation (SLR) measurements find a Korringa response at low temperatures, with dynamic (i.e. thermally activated) contributions dominating above ∼100 K. Below <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , we observe a small Hebel–Slichter coherence peak characterized by a superconducting energy gap <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">K</mml:mi> </mml:mrow> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>2.60</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mn>12</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi>meV</mml:mi> </mml:mrow> </mml:mrow> </mml:math> and modest Dynes-like broadening. Our measurements suggest a gap ratio <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>2</mml:mn> <mml:mi mathvariant="normal">Δ</
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.007 | 0.003 |
| Meta-epidemiology (narrow) | 0.004 | 0.007 |
| Meta-epidemiology (broad) | 0.002 | 0.009 |
| Bibliometrics | 0.002 | 0.005 |
| Science and technology studies | 0.006 | 0.008 |
| Scholarly communication | 0.005 | 0.009 |
| Open science | 0.009 | 0.008 |
| Research integrity | 0.007 | 0.008 |
| Insufficient payload (model declined to judge) | 0.706 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".